Search

Anion photoelectron spectra of ThSO− and ThS2− were recorded using the third (355 nm) harmonic of an Nd-YAG laser; these provided the measured vertical detachment energies of each anion. The experiments are supported by extensive coupled cluster calculations on ThSO, ThSO−, ThS2, and ThS2−, as well as the oxygen congeners ThO2 and ThO2−. The ab initio calculations, which included complete basis set extrapolations, spin–orbit effects using four-component coupled cluster, and higher-order correlation contributions through CCSDT(Q), yielded an adiabatic electron affinity for ThO2 that was within 0.02 eV of the previously determined experimental value. The singly occupied molecular orbital (SOMO) in all three anions corresponds primarily to the 7s orbital on Th. Successive substitution of S for each O in ThO2 leads to larger electron affinities and smaller bond angles in the neutral molecules, but larger angles in the anions. As demonstrated by Franck–Condon simulations of the spectra using the CCSD(T) spectroscopic constants, substitution of O by S significantly complicates the resulting detachment spectra due to the lower vibrational frequencies in the sulfur species. Overall the calculated vertical detachment energies are in very good agreement with the experiment. In addition to the adiabatic electron affinities of each species, atomization energies and heats of formation have also been determined via the FPD approach with expected uncertainties of 1–2 kcal/mol. [ABSTRACT FROM AUTHOR]

Anion photoelectron spectra of ThSO− and ThS2− were recorded using the third (355 nm) harmonic of an Nd-YAG laser; these provided the measured vertical detachment energies of each anion. The experiments are supported by extensive coupled cluster calculations on ThSO, ThSO−, ThS2, and ThS2−, as well as the oxygen congeners ThO2 and ThO2−. The ab initio calculations, which included complete basis set extrapolations, spin–orbit effects using four-component coupled cluster, and higher-order correlation contributions through CCSDT(Q), yielded an adiabatic electron affinity for ThO2 that was within 0.02 eV of the previously determined experimental value. The singly occupied molecular orbital (SOMO) in all three anions corresponds primarily to the 7s orbital on Th. Successive substitution of S for each O in ThO2 leads to larger electron affinities and smaller bond angles in the neutral molecules, but larger angles in the anions. As demonstrated by Franck–Condon simulations of the spectra using the CCSD(T) spectroscopic constants, substitution of O by S significantly complicates the resulting detachment spectra due to the lower vibrational frequencies in the sulfur species. Overall the calculated vertical detachment energies are in very good agreement with the experiment. In addition to the adiabatic electron affinities of each species, atomization energies and heats of formation have also been determined via the FPD approach with expected uncertainties of 1–2 kcal/mol. [ABSTRACT FROM AUTHOR]

Diamond is a semiconductor material with remarkable structural, thermal, and electronic properties that has garnered significant interest in the field of electronics. Although hydrogen (H) and oxygen (O) terminations are conventionally favored in transistor designs, alternative options, such as silicon (Si) and germanium (Ge), are being explored because of their resilience to harsh processing conditions during fabrication. Density-functional theory was used to examine the non-oxidized and oxidized group-IV (Si and Ge)-terminated diamond (100) surfaces. The (3 × 1) reconstructed surfaces feature an ether configuration and show relative stability compared with the bare surface. Hybrid-functional calculations of the electronic properties revealed reduced fundamental bandgaps (<1 eV) and lower negative electron affinities (NEAs) than those of H-terminated diamond surfaces, which is attributed to the introduction of unoccupied Si (Ge) states and the depletion of negative charges. Furthermore, oxidation of these surfaces enhanced the stability of the diamond surfaces but resulted in two structural configurations: ether and ketone. Oxidized ether configurations displayed insulating properties with energy gaps of ∼4.3 ± 0.3 eV, similar to H-terminated diamond (100) surfaces, whereas bridged ether configurations exhibited metallic properties. Oxidization of the metallic ketone configurations leads to the opening of relatively smaller gaps in the range of 1.1–1.7 eV. Overall, oxidation induced a shift from NEAs to positive electron affinities, except for the reverse-ordered ketone surface with an NEA of −0.94 eV, a value comparable to the H-terminated diamond (100) surfaces. In conclusion, oxidized group-IV-terminated diamond surfaces offer enhanced stability compared to H-terminated surfaces and display unique structural and electronic properties that are influenced by surface bonding. [ABSTRACT FROM AUTHOR]

We present a simple approximation to estimate the largest charge that a given molecule can hold until fragmentation into smaller charged species becomes more energetically favorable. This approximation solely relies on the ionization potentials, electron affinities of the parent and fragment species, and also on the neutral parent's dissociation energy. By parameterizing these quantities, it is possible to obtain analytical phase diagrams of polycationic stability. We demonstrate the applicability of this approach by discussing the maximal charge dependence on the size of the molecular system. A numerical demonstration for linear polyenes, monocyclic annulenes, and helium clusters is provided. [ABSTRACT FROM AUTHOR]

We performed high-level ab initio quantum chemical calculations, incorporating higher-order excitations, spin–orbit coupling (SOC), and the Gaunt interaction, to calculate the electron affinities (EAs) of alkaline earth (AE) metal atoms (Ca, Sr, Ba, and Ra), which are notably small. The coupled-cluster singles and doubles with perturbative triples [CCSD(T)] method is insufficient to accurately calculate the EAs of AE metal atoms. Higher-order excitations proved crucial, with the coupled-cluster singles, doubles, and triples with perturbative quadruples [CCSDT(2)Q] method effectively capturing dynamic electron correlation effects. The contributions of SOC (ΔESOs) to the EAs calculated using the multireference configuration interaction method with the Davidson correction, including SOC, positively enhance the EAs; however, these contributions are overestimated. The Dirac–Hartree–Fock (DHF)-CCSD(T) method addresses this overestimation and provides reasonable values for ΔESO (ΔESO−D). Employing additional sets of diffuse and core–valence correlation basis sets is critical for accurately calculating the EAs of AE metal atoms. The contributions of the Gaunt interaction (ΔEGaunt) to the EAs of AE metal atoms are negligible. Notably, the CCSDT(2)Q with the complete basis set limit + ΔESO−D + ΔEGaunt produced EA values for Ca, Sr, and Ba that closely aligned with experimental data and achieved accuracy exceeding the chemical accuracy. Based on our findings, the accurately proposed EA for Ra is 9.88 kJ/mol. [ABSTRACT FROM AUTHOR]

The isotope shifts in electron affinities of Pb were measured by Walter et al. [Phys. Rev. A 106, L010801 (2022)] to be −0.002(4) meV for 207–208Pb and −0.003(4) meV for 206–208Pb by scanning the threshold of the photodetachment channel Pb− ( S 3 / 2 ◦ 4 ) − Pb (3P0), while Chen and Ning reported 0.015(25) and −0.050(22) meV for the isotope shifts on the binding energies measured relative to 3P2 using the SEVI method [J. Chem. Phys. 145, 084303 (2016)]. Here we revisited these isotope shifts by using our second-generation SEVI spectrometer and obtained −0.001(15) meV for 207–208Pb and −0.001(14) meV for 206–208Pb, respectively. In order to aid the experiment by theory, we performed the first ab initio theoretical calculations of isotope shifts in electron affinities and binding energies of Pb, as well as the hyperfine structure of 207Pb−, by using the MCDHF and RCI methods. The isotope shifts in electron affinities of 207–208Pb and 206–208Pb are −0.0023(8) and −0.0037(13) meV for the 3P0 channel, respectively, in good agreement with Walter et al.'s measurements. The isotope shifts in binding energies relative to 3P1,2, −0.0015(8) and −0.0026(13) meV for 207–208Pb and 206–208Pb, respectively, are compatible with the present measurements. The hyperfine constant for the ground state of 207Pb− obtained by the present calculations, A ( S 3 / 2 ◦ 4 ) = − 1118 MHz, differs by a factor of 3 from the previous estimation by Bresteau et al. [J. Phys. B: At., Mol. Opt. Phys. 52, 065001 (2019)]. The reliability is supported by the good agreement between the theoretical and experimental hyperfine parameters of 209Bi. [ABSTRACT FROM AUTHOR]

The isotope shifts in electron affinities of Pb were measured by Walter et al. [Phys. Rev. A 106, L010801 (2022)] to be −0.002(4) meV for 207–208Pb and −0.003(4) meV for 206–208Pb by scanning the threshold of the photodetachment channel Pb− ( S 3 / 2 ◦ 4 ) − Pb (3P0), while Chen and Ning reported 0.015(25) and −0.050(22) meV for the isotope shifts on the binding energies measured relative to 3P2 using the SEVI method [J. Chem. Phys. 145, 084303 (2016)]. Here we revisited these isotope shifts by using our second-generation SEVI spectrometer and obtained −0.001(15) meV for 207–208Pb and −0.001(14) meV for 206–208Pb, respectively. In order to aid the experiment by theory, we performed the first ab initio theoretical calculations of isotope shifts in electron affinities and binding energies of Pb, as well as the hyperfine structure of 207Pb−, by using the MCDHF and RCI methods. The isotope shifts in electron affinities of 207–208Pb and 206–208Pb are −0.0023(8) and −0.0037(13) meV for the 3P0 channel, respectively, in good agreement with Walter et al.'s measurements. The isotope shifts in binding energies relative to 3P1,2, −0.0015(8) and −0.0026(13) meV for 207–208Pb and 206–208Pb, respectively, are compatible with the present measurements. The hyperfine constant for the ground state of 207Pb− obtained by the present calculations, A ( S 3 / 2 ◦ 4 ) = − 1118 MHz, differs by a factor of 3 from the previous estimation by Bresteau et al. [J. Phys. B: At., Mol. Opt. Phys. 52, 065001 (2019)]. The reliability is supported by the good agreement between the theoretical and experimental hyperfine parameters of 209Bi. [ABSTRACT FROM AUTHOR]

Rovibrational levels of low-lying electronic states of the gas-phase, diatomic molecules, PtH+ and PtH−, are computed on potential-energy functions obtained by using a hybrid spin–orbit configuration-interaction procedure. PtH− has a well-separated Σ 0 + + 1 ground state, while the first two electronic states of PtH+ ( Σ 0 + + 1 and 3Δ3) are nearly degenerate. Combining the experimental photoelectron (PE) spectra of PtH− with theoretical photodetachment spectroscopy leads to an improved value for the electron affinity of PtH, EA(PtH) = (1.617 ± 0.015) eV. When PtH− is a product of photodissociation of PtHCO2−, its PE spectrum is broad because of rotational excitation. Temperature-dependent thermodynamic functions and thermochemistry of dissociation are computed from the theoretical energy levels. Previously published energetic quantities for PtH+ and PtH− are revised. The ground 1Σ+ term of PtH+ is not well described using single-reference theory. [ABSTRACT FROM AUTHOR]

Rovibrational levels of low-lying electronic states of the gas-phase, diatomic molecules, PtH+ and PtH−, are computed on potential-energy functions obtained by using a hybrid spin–orbit configuration-interaction procedure. PtH− has a well-separated Σ 0 + + 1 ground state, while the first two electronic states of PtH+ ( Σ 0 + + 1 and 3Δ3) are nearly degenerate. Combining the experimental photoelectron (PE) spectra of PtH− with theoretical photodetachment spectroscopy leads to an improved value for the electron affinity of PtH, EA(PtH) = (1.617 ± 0.015) eV. When PtH− is a product of photodissociation of PtHCO2−, its PE spectrum is broad because of rotational excitation. Temperature-dependent thermodynamic functions and thermochemistry of dissociation are computed from the theoretical energy levels. Previously published energetic quantities for PtH+ and PtH− are revised. The ground 1Σ+ term of PtH+ is not well described using single-reference theory. [ABSTRACT FROM AUTHOR]

Understanding excited-state intramolecular proton transfer (ESIPT) is essential for designing organic molecules to enhance photophysical and luminophore properties in the development of optoelectronic devices. In this context, an attempt has been made to understand the impact of substituents on the ESIPT process of 2-(oxazolinyl)-phenol. Electron donating (EDG: –NH2, –OCH3, and –CH3) and electron withdrawing (EWG: –Cl, –Br, –COOH, –CF3, –CN, and –NO2) substitutions have been computationally designed and screened through density functional theory (DFT) and time-dependent density-functional theory (TDDFT) calculations. Furthermore, the ground state intramolecular proton transfer and ESIPT mechanisms of these designed luminophores are explored using the transition state theory. The results reveal that molecules with EDG show higher absorption and emission peaks than molecules with EWG and also indicate that the mobility of charge carriers in 2-(oxazolinyl)-phenol derivatives is significantly influenced by substituents. We found that the EWGs decrease the reorganization energy and increase the vertical ionization potential and electron affinity values, as well as the highest occupied molecular orbital-lowest unoccupied molecular orbital gap, compared to the EDG substituted molecules. Significantly, the excited state (S1) of the keto emission (K) form shows notably larger values for the EDG substitutions. The intersystem crossing pathway efficiency weakens with reduced spin–orbit coupling matrix element in the enol form with electron-donating substituents and vice versa in the keto form during S1–T3 transitions. Our research links intramolecular proton transfers and triplet generation, making these substituted molecules appealing for optoelectronic devices. Introducing EDGs, such as –NH2, boosts the ESIPT reaction in 2-(oxazolinyl)-phenol. This study guides designing ESIPT emitters with unique photophysical properties. [ABSTRACT FROM AUTHOR]

The addition of molecular dopants into organic semiconductors (OSCs) is a ubiquitous augmentation strategy to enhance the electrical conductivity of OSCs. Although the importance of optimizing OSC–dopant interactions is well-recognized, chemically generalizable structure–function relationships are difficult to extract due to the sensitivity and dependence of doping efficiency on chemistry, processing conditions, and morphology. Computational modeling for an integrated OSC–dopant design is an attractive approach to systematically isolate fundamental relationships, but requires the challenging simultaneous treatment of molecular reactivity and morphology evolution. We present the first computational study to couple molecular reactivity with morphology evolution in a molecularly doped OSC. Reactive Monte Carlo is employed to examine the evolution of OSC–dopant morphologies and doping efficiency with respect to dielectric, the thermodynamic driving for the doping reaction, and dopant aggregation. We observe that for well-mixed systems with experimentally relevant dielectric constants, doping efficiency is near unity with a very weak dependence on the ionization potential and electron affinity of OSC and dopant, respectively. At experimental dielectric constants, reaction-induced aggregation is observed, corresponding to the well-known insolubility of solution-doped materials. Simulations are qualitatively consistent with a number of experimental studies showing a decrease of doping efficiency with increasing dopant concentration. Finally, we observe that the aggregation of dopants lowers doping efficiency and thus presents a rational design strategy for maximizing doping efficiency in molecularly doped OSCs. This work represents an important first step toward the systematic integration of molecular reactivity and morphology evolution into the characterization of multi-scale structure–function relationships in molecularly doped OSCs. [ABSTRACT FROM AUTHOR]

We report on the high-resolution photodetachment spectroscopy of the cryogenically cooled anionic tellurium dimer (Te2−). The high-resolution resonant photoelectron spectrum yields an accurate electron affinity of 16 689.7(92) cm−1 or 2.0693(11) eV for Te2. Two resonant states of Te2− anions have been identified, positioned at 1092(17) cm−1 below and 250(11) cm−1 above the photodetachment threshold, respectively. The spectra of resonant two-photon detachment (R2PD) and autodetachment from a specific vibrational level through a Feshbach resonance exhibit notable non-Franck–Condon behaviors. Using the spectroscopic data from the current experiment, the equilibrium bond distances and spectroscopic constants of the ground state and two electronically excited states of Te2− were determined. [ABSTRACT FROM AUTHOR]

EA-EOM-CCSD electron affinities and LUMO energies of various Kohn–Sham density functional theory (DFT) methods are calculated for an a priori IP benchmark set of 64 small, closed-shell molecules. The purpose of these calculations was to investigate whether the QTP KS-DFT functionals can emulate EA-EOM-CC with only a mean-field approximation. We show that the accuracy of DFT—relative to CCSD—improves significantly when elements of correlated orbital theory are introduced into the parameterization to define the QTP family of functionals. In particular, QTP(02), which has only a single range separation parameter, provides results accurate to a MAD of < 0.15 eV for the whole set of 64 molecules compared to EA-EOM-CCSD, far exceeding the results from the non-QTP family of density functionals. [ABSTRACT FROM AUTHOR]

The electronic properties of SO2 at the surface of a water cluster were investigated by employing a combination of Born–Oppenheimer molecular dynamics and electron propagator theory (EPT). In our work, we utilized a revised version of the Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional, which incorporates empirical corrections for dispersion interactions in line with a recent study of the air–water interface conducted by Ohto et al. [J. Phys. Chem. Lett. 10(17), 4914–4919 (2019)]. Polarization effects induce a significant broadening of the electron binding energy distribution, as predicted by EPT. This broadening can result in a substantial increase in electron affinity, impacting the chemical reactivity of SO2 at the air–water interface, a topic of significant and recent research interest. We discuss the relationship between electron binding energies (EBEs) and the specific connections of SO2 to water. The results indicate that configurations involving an OS⋯H bond tend to yield higher electron affinities compared to complex formation through S⋯OW bonds. Surprisingly, SO2 molecules not bound to water molecules according to a specific criterion may also exhibit higher electron affinities. This feature can be explained by the role played by the polarization field from water molecules. Our best estimate for the HOMO–LUMO (H–L) gap of SO2 at the surface of a water cluster is 11.6 eV. Very similar H–L gaps are predicted for isolated and micro-solvated SO2. Fukui functions for the gas phase, and the micro-solvated SO2–H2O complex supports the view that the LUMO is predominantly localized on the SO2 moiety. [ABSTRACT FROM AUTHOR]

A practical ab initio composite method for modeling x-ray absorption and non-resonant x-ray emission is presented. Vertical K-edge excitation and emission energies are obtained from core-electron binding energies calculated with spin-projected ΔHF/ΔMP and outer-core ionization potentials/electron affinities calculated with electron propagator theory. An assessment of the combined methodologies against experiment is performed for a set of small molecules containing second-row elements. [ABSTRACT FROM AUTHOR]

Electron-driven processes in isolated curcumin (CUR) molecules are studied by means of dissociative electron attachment (DEA) spectroscopy under gas-phase conditions. Elementary photostimulated reactions initiated in CUR molecules under UV irradiation are studied using the chemically induced dynamic nuclear polarization method in an acetonitrile solvent. Density functional theory is applied to elucidate the energetics of fragmentation of CUR by low-energy (0–15 eV) resonance electron attachment and to characterize various CUR radical forms. The adiabatic electron affinity of CUR molecule is experimentally estimated to be about 1 eV. An extra electron attachment to the π1* LUMO and π2* molecular orbitals is responsible for the most intense DEA signals observed at thermal electron energy. The most abundant long-lived (hundreds of micro- to milliseconds) molecular negative ions CUR– are detected not only at the thermal energy of incident electrons but also at 0.6 eV, which is due to the formation of the π3* and π4* temporary negative ion states predicted to lie around 1 eV. Proton-assisted electron transfer between CUR molecules is registered under UV irradiation. The formation of both radical-anions and radical-cations of CUR is found to be more favorable in its enol form. The present findings shed some light on the elementary processes triggered in CUR by electrons and photons and, therefore, can be useful to understand the molecular mechanisms responsible for a variety of biological effects produced by CUR. [ABSTRACT FROM AUTHOR]

We report a study on the electronic structure and chemical bonding of the BiB molecule using high-resolution photoelectron imaging of cryogenically cooled BiB− anion. By eliminating all the vibrational hot bands, we can resolve the complicated detachment transitions due to the open-shell nature of BiB and the strong spin–orbit coupling. The electron affinity of BiB is measured to be 2.010(1) eV. The ground state of BiB− is determined to be 2Π(3/2) with a σ2π3 valence electron configuration, while the ground state of BiB is found to be 3Σ−(0+) with a σ2π2 electron configuration. Eight low-lying spin–orbit excited states [3Σ−(1), 1Δ(2), 1Σ+(0+), 3Π(2), 3Π(1), 1Π(1)], including two forbidden transitions, [3Π(0−) and 3Π(0+)], are observed for BiB as a result of electron detachment from the σ and π orbitals of BiB−. The angular distribution information from the photoelectron imaging is found to be critical to distinguish detachment transitions from the σ or π orbital for the spectral assignment. This study provides a wealth of information about the low-lying electronic states and spin–orbit coupling of BiB, demonstrating the importance of cryogenic cooling for obtaining well-resolved photoelectron spectra for size-selected clusters produced from a laser vaporization cluster source. [ABSTRACT FROM AUTHOR]

Hybrid capacitive deionization (HCDI) emerges as a burgeoning electrochemical desalination technology due to the utilization of profitable pseudocapacitive reactions. Although tunable organic compounds are potential faradaic electrode materials, their insufficient active sites and high water‐solubility restrict practical HCDI applications. Herein, a pseudocapacitive organic polymer (PNDS) is proposed with diverse redox‐active sites for electrochemical deionization. The pronounced molecular aromaticity and strong π‐electron delocalization not only endow PNDS polymer with framework rigidity, but refine its electronic structure to bolster redox activity and electron affinity. As an electrode material, the PNDS polymer demonstrates a substantial pseudocapacitive capacitance of 390 F g−1 and sustains long‐term stability at 96.3% after 5000 cycles, surpassing reported Na+‐capturing organic electrodes. In‐operando monitoring techniques and theoretical calculations reveal efficient Na+ capture at the C═N and C═O redox‐active sites within the PNDS electrode during repeated electrosorption processes. As a conceptual demonstration, a high‐performance HCDI device equipped with the PNDS electrode exhibits an impressive salt removal capacity (66.4 mg g−1), a rapid removal rate (2.2 mg g−1 min−1) and stable regeneration property. More importantly, an integrated desalination system is engineered to rapidly and repeatedly treat saltwater resources for human consumption and agricultural irrigation, highlighting its promising prospects for high‐efficiency desalination applications. [ABSTRACT FROM AUTHOR]

The trifluoromethylation of C88(7) fullerene has been systematically studied using an energy‐controlled consecutive CF3 addition approach. The thermodynamically favored C88(7)(CF3)2n isomers with 2n = 2–20 were predicted at the DFT B3LYP‐D3BJ/6–311G* level of theory for the first time, in harmony with the two experimentally characterized isomers C88(7)(CF3)12/16. It was found that these stable isomers are formed mainly by 1,4‐additions of CF3 groups, and meanwhile, there are a few stable isomers with isolated CF3 groups for 2n ≤ 12, with ortho addition for 2n > 12, and with triple‐hexagon‐junction addition for the highest degree of trifluoromethylation (2n ≥ 18). The addition patterns of CF3 groups were discussed in terms of the local structural motif of the pristine cage and the formation of stabilizing substructures of local aromaticity. The possible trifluoromethylation pathways of C88(7) were proposed on the basis of the relative Gibbs free energies. The results show that almost all the intermediate isomers for the thermodynamically most stable isomers of C88(7)(CF3)2n possess low relative Gibbs free energies (below 14 kJ·mol−1). Moreover, the hardness, chemical potential, electrophilicity index, electron affinity, HOMO and LUMO energies, and HOMO–LUMO gaps of the thermodynamically most stable C88(7)(CF3)2n isomers were also calculated. [ABSTRACT FROM AUTHOR]

The letter comments on a study that prepared P-type zeolite from coal fly ash for adsorption of heavy metals like Cr3+, Ni2+, and Co2+. The research focused on understanding the thermodynamics of the adsorption process, revealing an enthalpy-entropy compensation phenomenon. By analyzing the data, a predictive model was developed to estimate the adsorption of other heavy metals onto the zeolite. The study suggests that the zeolite may effectively remove heavy metals like In, Mo, Zn, As, and Fe, contributing to environmental safety. [Extracted from the article]

The reactions of a series of organic polynitriles with [Te4][AsF6]2 in liquid SO2 solution lead either to reduction of [Te4]2+ to elemental tellurium or to the formation of coordination polymers. With 1,3‐dicyanobenzene (1,3‐DCB), 1,4‐dicyanobenzene (1,4‐DCB), 1,2,4,5‐tetracyanobenzene (TCB), tetracyanoethylene (TCNE) and tetracyanochinodimethane (TCNQ) the coordination complexes [Te4][AsF6]2 ⋅ 2(1,3‐DCB), [Te4][AsF6]2 ⋅ 3(1,4‐DCB) ⋅ 2SO2, [Te4][AsF6]2 ⋅ TCB, [Te4][AsF6]2 ⋅ TCNE and [Te4][AsF6]2 ⋅ TCNQ ⋅ 8 SO2 were isolated and characterized by crystal structure analyses and vibrational Raman spectroscopy. The nitriles are coordinated to the square‐planar clusters forming 1D chains, 2D arrangements and 3D networks. Tetrakis(dicyanomethylene)cyclobutendiide [C4(C{CN}2)4]2− is oxidized by [Te4]2+ to the neutral cyanocarbon C4(C{CN}2)4, structurally representing a 4[radialene]. The ionization potentials and electron affinities of the cyanamide anion, cyanogen, 1,2‐DCB, 1,3‐DCB, 1,4‐DCB, TCB, C4(C{CN}2)4, TCNE and TCNQ and those polynitriles, which cause reduction of [Te4]2+, were calculated at coupled‐cluster level of theory in order to examine possible reasons for the stability of the coordination polymers based on electronic properties of the nitriles. [ABSTRACT FROM AUTHOR]

Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A resonance-enhanced GaInAsSb nanopillar array negative electron affinity potential photocathode based on Mie resonance excitation at infrared wavelengths can significantly enhance the absorption and quantum efficiency of nanopillar arrays. Our study indicates the different periodic structures have very little effect on the QE for the nanopillar arrays. However, the smaller the period of the array, the higher the quantum efficiency is achieved, but the probability of being collected by the anode is reduced, so a compromise should be considered in the structure design. Moreover, the incident light inclination and the external electric field can significantly affect the quantum efficiency of the nanopillar arrays. The photocathodes studied here have a quantum efficiency of over 5.7% with an angle of incidence of 30∘ and an applied electric field intensity of 1.2 V/ μ m. This work provides an important reference and theoretical basis for the design and optimization of resonance-enhanced GaInAsSb nanopillar arrays photocathode. [ABSTRACT FROM AUTHOR]

Two binuclear Gadolinium(III) (Gd) complex [Gd2(L1)2(H2L3)2(NO3)2] (1) and [Gd2(L2)2(H2L3)2(NO3)2] (2) were obtained by using 2‐hydroxybenzaldehyde or 2‐hydroxy‐1‐naphthaldehyde, 2‐aminophenol, pyridin‐2‐ylmethanamine and Gd(NO3)3 ⋅ 6H2O in CH3CN (H2L1=(E)‐2‐((2‐hydroxybenzylidene)amino)phenol, H2L2=(E)‐1‐(((2‐hydroxyphenyl)imino)methyl)naphthalen‐2‐ol, H2L3=pyridin‐2‐ylmethanamine). Structural analysis suggests that all the ligands as protective units protect the central Gd(III) ions at the periphery. Magnetization studies exhibited magnetocaloric effect of 14.45 J ⋅ kg−1 ⋅ K−1 at 4 K under ΔH=7 T for complex 1 and 12.69 J ⋅ kg−1 ⋅ K−1 at 2 K under ΔH=7 T for complex 2. In complexes 1 and 2, although the coordination configurations are the same, the significant difference in MCE may be due to the adjustments of the peripheral ligands leading to changes in the coordination field strength. The electron affinity of the ligands can impact the interaction between the ligands and Gd(III) ions. [ABSTRACT FROM AUTHOR]

A series of 2,2′‐(1,4‐phenylene)bis(N‐substituted phenylthiazolidine‐4‐amide) derivatives, denoted as (A3–9), were synthesized, and characterized for their potential applications against prostate cancer cells (PC3), and Candida albicans fungi. These compounds incorporate various substituents on the phenyl ring such as 4‐NO2, 3‐NO2, 4‐COCH3, 4‐H, 4‐OCH3, 4‐OCH2CH3, and 4‐Cl. The chemical structures of these derivatives were confirmed by NMR, FTIR, and mass spectroscopy. Biological assays, utilizing the MTT assay for prostate cancer cells (PC3) and the disk diffusion assay for Candida albicans fungi, were conducted to evaluate the bioactivity of these compounds. The results revealed promising cytotoxic and antifungal activities. Specifically, compounds A3 (IC50=69.74±0.96), A4 (IC50=63.64±0.950), and A9 (IC50=57.14±0.88 μg/mL) exhibited notable potency against PC3 cells, while A7 and A8 exhibited considerable antifungal efficacy against Candida albicans with MIC of 312 μg/mL. Moreover, density functional theory (DFT) simulations were used to study electronic properties and reactivity descriptors such as energy gap (Eg), ionization potential (IP), electron affinity (EA), chemical potential (μ), chemical hardness (η), global softness (σ), electronegativity (χ), and electrophilicity (ω) to gain a better understanding of the Structure‐Activity Relationship (SAR). Molecular docking analysis against DNA Gyrase and EGFR tyrosine kinase enzymes revealed strong binding interactions of the investigated molecules within their active sites, making them valuable candidates for further development as therapeutic agents against prostate cancer and fungal infections. POM analysis indicates the presence of two antifungal pharmacophore sites (O1δ−, O2δ−) and (O3δ−, O4δ−), as well as two antitumor pharmacophore sites (O1δ−, NH1δ+) and (O4δ−, NH2δ+). [ABSTRACT FROM AUTHOR]

In charged water microdroplets, which occur in nature or in the lab upon ultrasonication or in electrospray processes, the thermodynamics for reactive chemistry can be dramatically altered relative to the bulk phase. Here, we provide a theoretical basis for the observation of accelerated chemistry by simulating water droplets of increasing charge imbalance to create redox agents such as hydroxyl and hydrogen radicals and solvated electrons. We compute the hydration enthalpy of OH− and H+ that controls the electron transfer process, and the corresponding changes in vertical ionization energy and vertical electron affinity of the ions, to create OH• and H• reactive species. We find that at ~ 20 − 50% of the Rayleigh limit of droplet charge the hydration enthalpy of both OH− and H+ have decreased by >50 kcal/mol such that electron transfer becomes thermodynamically favorable, in correspondence with the more favorable vertical electron affinity of H+ and the lowered vertical ionization energy of OH−. We provide scaling arguments that show that the nanoscale calculations and conclusions extend to the experimental microdroplet length scale. The relevance of the droplet charge for chemical reactivity is illustrated for the formation of H2O2, and has clear implications for other redox reactions observed to occur with enhanced rates in microdroplets. Redox reactions exhibit different thermodynamics and kinetics in water microdroplets compared to the bulk. Here, the authors use reactive molecular dynamics to show the importance of charged reactive species in explaining reactivity under confinement. [ABSTRACT FROM AUTHOR]

A computational study on the intricate mechanism of thiophene ring‐fragmentation (TRF) in the UV photodissociation, dissociative ionization, and dissociative electron attachment process has been performed. The complete fragmentation process is studied using high level G4 composite method for neutral, cationic, and anionic species by elucidating a detailed mechanism for various reaction channels. The study shows that for neutral thiophene, the major pathway is the migration of H atom and subsequent fragmentation through a transition state yielding acetylene (HC≡CH) and H2C=C=S. However, for the thiophene cation, the acetylene (HC≡CH)+H2C=C=S+ channel is a two‐step and barrier less process. The onset of CH3+HC=C=C=S channel has been observed in both the thiophene cation and anion which was absent in the neutral analogue. Similarly, the onset of H2S+HC≡C—C≡CH channel has been found to operate only in the thiophene cation. Others, such as HCS and HS elimination channels have been found in all the species showing similar dissociation mechanism. For the thiophene anion, the TRF process is very much similar to that of thiophene cation. However, the reaction enthalpies of the various elimination channels in the anionic species are lower as compared to that of cationic species. During the study, the ionization energies and electron affinities of various molecules/radicals produced during the fragmentation process of thiophene were also computed. [ABSTRACT FROM AUTHOR]

This article explores the ionization characteristics of 19 amino acids using positive-ion Helium-Desorption Atmospheric Pressure Chemical Ionization Mass Spectrometry (He-DART-MS). The study reveals that multiple hydrogenation radical adducts of amino acids were observed during He-DART-MS analysis, with heterocyclic amino acids being more likely to produce these adducts. Aromatic amino acids, on the other hand, were less likely to exhibit this phenomenon. The findings provide valuable insights for the analysis of related compounds using He-DART-MS. The study received support from the Science and Technology Development Planning Project of Jilin Province and the Project for Outstanding Young Scientific and Technological Talents of Changchun University of Chinese Medicine. [Extracted from the article]

In the field of thin‐film solar cells, there is a growing need for cadmium‐free buffer layers and fabrication techniques that are both cost‐effective and environmentally friendly. In this study, the deposition of In2S3 and In–Ga–S thin films as alternative buffer layer materials in thin‐film solar cells, using mist chemical vapor deposition (CVD) at atmospheric pressure, is focused on. Indium diethyldithiocarbamate (DTC) and gallium DTC dissolved in dehydrated tetrahydrofuran are used as precursors. The deposited In2S3 demonstrates a wider direct bandgap (Eg‐dir ≈ 2.7 eV) than CdS, showing a potential for reducing parasitic absorption. Introducing a certain amount of gallium into In2S3 induces structural changes, resulting in a wider bandgap material. This bandgap widening primarily lowers electron affinity, making it beneficial for absorber materials with wider bandgap energies. Overall, the In2S3 and In–Ga–S thin films deposited via mist CVD exhibit preferable properties as alternatives to the CdS buffer layer. Moreover, the deposition technique proposed in this study can be adapted for the nonvacuum and cost‐effective deposition of other sulfide materials. [ABSTRACT FROM AUTHOR]

Exciton binding energy (Eb) is understood as the energy required to dissociate an exciton in free‐charge carriers, and is known to be an important parameter in determining the performance of organic opto‐electronic devices. However, the development of a molecular design to achieve a small level of Eb in the solid state continues to lag behind. Here, to investigate the relationship between aggregation and Eb, star‐shaped π‐conjugated compounds DBC‐RD and TPE‐RD were developed using dibenzo[g,p]chrysene (DBC) and tetraphenylethylene (TPE). Theoretical calculations and physical measurements in solution showed no apparent differences between DBC‐RD and TPE‐RD, indicating that these molecules possess similar properties on a single‐molecule level. By contrast, pristine films incorporating these molecules showed significantly different levels of electron affinity, ionization potential, and optical gap. Also, DBC‐RD had a smaller Eb value of 0.24 eV compared with that of TPE‐RD (0.42 eV). However, these molecules showed similar Eb values under dispersed conditions, which suggested that the decreased Eb of DBC‐RD in pristine film is induced by molecular aggregation. By comparison with TPE‐RD, DBC‐RD showed superior performances in single‐component organic solar cells and organic photocatalysts. These results indicate that a molecular design suitable for aggregation is important to decrease the Eb in films. [ABSTRACT FROM AUTHOR]

Context: Indandione-based materials are promising candidates for organic electronics, offering high electron mobility and tunable optoelectronic properties. In this study, we explore the optoelectronic and photovoltaic properties of indandione-based donor–acceptor (D-A) materials, specifically (R1) and (R2), by introducing malononitrile group acceptors into their molecular structure. These strong electron-withdrawing acceptors are designed to enhance charge transfer and overall material performance. The designed molecules (DM1–DM4) exhibit a low optical band gap of approximately 1.77 eV, significantly lower than the reference materials (R1 and R2) at around 2.24 eV in a solvent environment. Among the designed molecules, DM4 stands out with superior photovoltaic parameters, including a narrow optical band gap (1.77 eV), higher electron affinity (3.49 eV), an extended excited state lifetime (10.0 ns) owing to its low electron and hole reorganization energies (λe ~ 0.13 eV and λh ~ 0.24 eV), and improved short-circuit current density (Jsc) of ~ 15.73 mA/cm2. Notably, DM4 achieves a power conversion efficiency (PCE) of ~ 18.5%, making it an excellent candidate for device applications. Method: A comprehensive computational investigation was carried out on indandione-based D-A materials with malononitrile group acceptors (DM1–DM4) using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, as implemented in Gaussian 16 software. We examined the electronic and optical properties of the proposed molecules through frontier molecular orbital (FMO) analysis, UV–Vis absorption spectra, density of states (DOS), exciton binding energy (Eb), and transition density matrix (TDM) analysis, utilizing GaussView 6.0 and Multiwfn 3.8 software. The photovoltaic parameters and power conversion efficiency (PCE) were evaluated using the Scharber and Alharbi models. [ABSTRACT FROM AUTHOR]

AbstractThe quantum chemical properties of 5-hydroxymethylfurfural were investigated using Density Functional Theory alongside vibrational spectroscopy. Key outcomes included optimizing molecular structure, vibrational frequencies, and various molecular parameters. By comparing DFT results with experimental infrared spectra, molecular motion was clarified. Reactive sites were identified through Molecular Electrostatic Potential and Fukui function analyses. Hirshfeld surface analysis revealed insights into the crystal structure’s intermolecular interactions and hydrogen bonding. Time-dependent Density Functional Theory combined with the Polarizable Continuum Model provided Ultraviolet spectra, highlighting charge transfer between the highest occupied and lowest unoccupied molecular orbitals. The compound’s electronegativity (4.7239) and electron affinity were assessed. Biological studies, including drug-likeness evaluations and molecular docking, also demonstrated potential physiological benefits, mainly through the compound’s low binding energy. A 100-nanosecond molecular dynamics simulation of the 5-HMF-4LB4 complex revealed its stability and dynamic behavior through analyses of Root Mean Square Deviation, Root Mean Square Fluctuation, hydrogen bonding, Solvent Accessible Surface Area, and radius of gyration. [ABSTRACT FROM AUTHOR]

Para-tert-butylthiacalix[4]arenimines with mono- and distally substituted functional groups have been examined in terms of their structure and spectra. The structure and H-bonds of these compounds can be studied by comparing their vibrational and NMR spectra. The spectra of several conformations of the molecules TCA1-4 were calculated. For the molecules TCA3 and TCA4, the most stable conformation is a distorted cone (DC2) with the same imine or phthalimide group orientation, consequently. The least stable conformation is pinched cone (PC). The conformations of molecules TCA2, TCA3, and TCA4 are DC1 and DC2, respectively. H-bonds in the molecules TCA1-4 alter their supramolecular properties. Ionization energy and dipole moment decrease as monosubstituted thiacalixarene (TCA1) transforms into disubstituted TCA2. In this instance, there is an increase in softness, electrophilicity, chemical potential, and electron affinity. An increase in the number of methylene groups in disubstituted thiacalixarenes from TCA4 to TCA2 is accompanied by an increase in ionization energy, electron affinity, and electrophilicity. [ABSTRACT FROM AUTHOR]

Over the past decade, there has been significant improvement in the efficiency of hybrid perovskite solar cells (PSCs). When discussing hybrid organic‐inorganic PSCs, it is important to consider stability and toxicity as crucial factors. Additional research is necessary to thoroughly investigate their potential for enhancing market accessibility. Research explores a comprehensive analysis of the photovoltaic performance of CsSnBr3‐based PSCs configurations. Solar cell capacitance simulator‐1D is utilized to study a variety of electron transport layers (ETLs) such as CeO2, TiO2, SnO2, WO3, MZO, ZnO, IGZO, PCBM, WS2, and C60. Examining the impact of different parameters on the performance of CsSnBr3‐based PSCs by precisely modifying spiro‐OMeTAD as a hole transport layer (HTL) is primarily concentrated on. Utilizing a well‐organized arrangement, FTO/ETLs/CsSnBr3/Spiro‐OMeTAD/Au, out of the mentioned ETLs, it has been observed that only four oxides based ETLs (CeO2, SnO2, WO3, and ZnO) are highly compatible and suitable for CsSnBr3‐based PSC. The photovoltaic performance of various ETLs is examined. The power conversion efficiencies of CeO2, SnO2, WO3, and ZnO ETLs are 18.42%, 22.06%, 21.35%, and 21.87% achieved by optimizing various parameters such as thickness, defect density, doping concentration, and electron affinity of all the layers. The validation and simulation findings indicate that CsSnBr3 has significant potential when combined with suitable ETLs and spiro‐OMeTAD as an HTL. [ABSTRACT FROM AUTHOR]

In this study, density functional theory (DFT) calculations were initially conducted to explore the molecular structure, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), LUMO-HOMO energies, as well as the excited states of new piperazine derivatives using the CAM-B3LYP/Def2TZV level of theory. Detailed quantum molecular descriptors for the compounds, including ionization potential (IP), electron affinities (EA), hardness (η), softness (S), electronegativity (μ), electrophilic index (ω), electron-donating power (ω−), electron accepting power (ω+), and energy gap (Eg), were calculated. The chemical properties and bioactivity of these compounds, such as molecular weight, lipophilicity, number of hydrogen bond (HB) donors and acceptors, molar refractivity, polarity, solubility, flexibility and saturation, were also investigated. Subsequently, a molecular docking study was performed to identify effective compounds that could act as strong inhibitors against Parkinson's Disease. The Michaelis-Menten constant (Km) was determined using the CAM-B3LYP/Def2TZV level of theory. The binding energy between the protein with ID:5CGJ and the organic compounds demonstrated excellent binding affinity. Therefore, the structures: 4-(4-methylpiperazin-1-yl)-4-oxo-N-(4-sulfamoylphenyl)butanamide (21), N-(4-((4-methylpiperazin-1-yl)methyl)phenyl)-4-(morpholinomethyl) benzamide (22), cаn bе usеd for potential application аgаinst Parkinson's Disease. [ABSTRACT FROM AUTHOR]

This study investigates the functionalization of graphene nanotube (GNTs) conjugates with an amino compound called 1‐amino‐2‐hydroxy‐4‐naphthalene sulfonic acid (AHNSA‐GNTs). The study also evaluates the potential application of these conjugates in dyeing processes. The goal is to modify GNTs to enhance their interaction with dyes, thus improving the efficiency of dyeing textiles and the colorfastness of the resulting products. Multiple characterization methods, such as X‐ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to get a better look at the composites. The findings of the study indicate that AHNSA‐GNTs composites improve dye retention on wool fibers, which leads to a reduction in the consumption of excess dye and water. Density Functional Theory (DFT) calculations were utilized to investigate the electronic properties and binding energies of the functionalized CNTs, providing insights into the molecular interactions between the CNTs and amino compounds. Overall, this study highlights the promising applications of graphene nanotubes in sustainable textile processes. Frontier molecular orbitals (FMOs) and global reactivity descriptors serve as key tools for understanding the stability and chemical reactivity of compounds. These tools were used to calculate FMOs and electronic parameters of compounds 1 and 2 at the B3LYP/6‐31G(d) level of theory. The study examined the highest occupied molecular orbital (HOMO)‐lowest unoccupied molecular orbital (LUMO) energy gap, which provides insights into molecular stability and reactivity. Various physical properties were derived from these calculations, including electron affinity (EA) and ionization potential (IP) to LUMO and HOMO energies. Compound 2 emerged as the most efficient electron donor, possessing the highest HOMO energy, while compound 1 excelled as the best electron acceptor with the highest LUMO energy. [ABSTRACT FROM AUTHOR]

The development of n‐type organic thermoelectric materials, especially π‐conjugated small molecules, lags far behind their p‐type counterparts, due primarily to the scarcity of efficient electron‐transporting molecules and the typically low electron affinities of n‐type conjugated molecules that leads to inefficient n‐doping. Herein, the n‐doping of two functionalized (carbonyl vs dicyanovinylene) indenofluorene‐based conjugated small molecules, 2,8‐bis(5‐(2‐octyldodecyl)thien‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐dione (TIFDKT) and 2,2′‐(2,8‐bis(3‐alkylthiophen‐2‐yl)indeno[1,2‐b]fluorene‐6,12‐diylidene)dimalononitrile (TIFDMT) are demonstrated, with n‐type dopant N‐DMBI. While TIFDKT shows decent miscibility with N‐DMBI, it can be hardly n‐doped owing to its insufficiently low LUMO. On the other hand, TIFDMT, despite a poorer miscibility with N‐DMBI, can be efficiently n‐doped, reaching a respectable electrical conductivity of 0.16 S cm−1. Electron paramagnetic resonance measurements confirm the efficient n‐doping of TIFDMT. Based on density functional theory (DFT) calculations, the LUMO frontier orbital energy of TIFDMT is much lower, and its wave function is more delocalized compared to TIFDKT. Additionally, the polarons are more delocalized in the n‐doped TIFDMT. Remarkably, as indicated by the grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), the molecular order for TIFDMT thin‐film is enhanced by n‐doping, leading to more favorable packing with edge‐on orientation and shorter π‐π stacking distances (from 3.61 to 3.36 Å). This induces more efficient charge transport in the doped state. Upon optimization, a decent thermoelectric power factor of 0.25 µWm−1K−2 is achieved for n‐doped TIFDMT. This work reveals the effect of carbonyl vs dicyanovinylene on the n‐doping efficiency, microstructure evolution upon doping and thermoelectric performance, offering a stepping stone for the future design of efficient n‐type thermoelectric molecules. [ABSTRACT FROM AUTHOR]

Here, we describe a set of coupled experimental and theoretical analyses. The introduction of one and two additional cyano groups in the carboheptahelicene backbone enhance its electron‐accepting properties. New carboheptahelicene derivatives are synthesized, and relevant characterizations of structural features, photophysical and electrochemical properties, and structure‐property relationships are described. This present work concerns the use of the density functional theory (DFT) to highlight the structural and the optoelectronic properties of carboheptahelicene derivatives and comparing the obtained findings with the experimental ones. The experimental and theoretical spectra (UV‐Vis absorption and photoluminescence) provide excellent concurrence. Afterward, molecular structures, structural parameters, molecular electrostatic potential (MEP), highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of frontier molecular orbitals (FMOs) are constructed. Some other optoelectronic parameter including electron affinity (EA), ionization potential (IP), and some reactive descriptor such as chemical potential (μ), global hardness (η), electronegativity (χ) and the overall electrophilicity index (ω) are determined and indicating its potential uses as an active layer in optoelectronic efficient devices. The topological methods such as electron localization function (ELF), localization orbital locator (LOL) and the reduced density gradient method (RDG) were also conducted to clarify the strengths and kinds of interactions. [ABSTRACT FROM AUTHOR]

This study investigates symmetrical/asymmetrical vertical electrolyte‐insulated semiconductor Tunnel field effect transistors (TFETs) (SV‐EIS‐TFET/ASV‐EIS‐TFET) for their application as pH biosensors. On the basis of device‐level simulations, the underlying physics of all architectures is explored and the comparative biosensing abilities of pH biosensors are evaluated. A vertical electrolyte Bio‐TFET with overlapping electrodes is presented in this study. The pH response is measured by observing the change in drain current and potential when the pH of the injected solution transitions from a lower to a higher level. As an intrinsic semiconductor material, electrons and holes in the electrolyte represent mobile ions in the solution. The region of the electrolyte has an electron affinity of 1.32 eV, a bandgap of 1.12 eV, and a dielectric constant of 78. Double gate structures raise concerns about correctly aligning the right and left gates because of their sensitivity impact. An analysis of the effect of gate misalignment on biosensor surface potentials, drain currents, and transconductance is presented. Furthermore, pH value ranges of 1–14 are considered for various sensitivity parameters. Simulations are performed using Silvaco TCAD for the SV‐EIS‐TFET and ASV‐EIS‐TFET biosensors. [ABSTRACT FROM AUTHOR]

This study uses density functional theory to investigate boron nitride nanoclusters functionalized with amino acids for enhanced binding of bisphenols A (BPA) and Z (BPZ) to mimic the estrogen-related receptor gamma. Three categories of nanoclusters were examined: pristine B12N12, and those which were germanium-doped for boron or nitrogen. The study reveals that hydrogen bonding patterns and molecular stability are significantly influenced by the type of functional group and the specific amino acids involved. Ge-doping generally enhances the binding stability and spontaneity of the nanocluster–amino acid–bisphenol complexes, with Glu 275 emerging as the most stable binding site. The analysis of electronic properties such as energy gap, ionization potential, electron affinity, and chemical hardness before and after bisphenol binding indicates a general trend of increased reactivity, particularly in Ge-doped nanoclusters. The findings highlight the potential of these nanocluster composites in applications requiring high reactivity and electron mobility, such as pollutant removal and drug delivery. [ABSTRACT FROM AUTHOR]

With ultra-wide bandgap and outstanding thermal properties, diamond-based high-power devices have excellent application prospects. The crystal structure and electronic property of the metal/hydrogen-terminated diamond (H-diamond) interfaces have been extensively studied experimentally, but the Schottky barrier height (SBH) theory at the metal/H-diamond interface has not been systematically investigated yet. In this work, SBHs of interfaces formed by H-diamond (111) surfaces with 12 metals (Y, Sc, Mg, Ag, Al, Ti, Cu, Co, Pd, Ni, Au and Pt) are investigated using ab-initio calculations. The fitted curve of the SBH with respect to the metal work function is obtained with a Fermi pinning factor of 0.30, which is close to the empirical value of 0.36. Due to the negative electron affinity of H-diamond, Schottky contacts can be formed with low work function metals, which is useful in device design to regulate the SBH and it is relatively easier to form ohmic contacts with high work function metals, leading to low contact resistances. Our work sheds light on the rational design of diamond-based semiconductor devices with low contact resistances. [ABSTRACT FROM AUTHOR]

Two sets of co-formers, polyfluorinated arylenediamines with variable structural elements and macrocyclic ethers of different sizes, were used to study the patterns of self-assembly of co-crystals and to rank the intermolecular interactions. The co-crystallization stoichiometry was found to increase from 1 : 1 to 2 : 1 in the series trifluoro-1,3-phenylenediamine, 2,4-diaminotrifluoropyridine, and 2,4-diaminotrifluoronitrobenzene and with decreasing crown ether size due to restructuring of guest--host interactions and forming guest-guest interactions. 18-Crown-6 and 15-crown-5 ethers form the typical N--H...Ocr H-bonds connecting two Ocr atoms with one bifunctional proton donor NH2; when going to 12-crown-4, two Ocr atoms become connected with the Hamino atoms of two arylenediamine molecules. Modes of guest--guest bonding and supramolecular motifs in 2 : 1 co-crystals are determined by HB acceptors and p + π systems in arylenediamine: o-N--H...Nhet and p-N--H...F interactions form face-to-face dimers united in a chain; p-N-H...Onitro and o-N--H...Onitro contacts generate head-to-tail and head-to-side chains; π...π and X...π (X = F, O, N) electron interactions form off-set stacks. Quantum chemical calculations reveal an increase of the packing enthalpies and bonding energies with increasing arylenediamine electron affinity and crown ether size. According to MEP, BCP and NCI analyses, these effects are caused either by strengthening of the interactions due to a greater electrostatic contribution, or by multiplying bonding contacts. Quantifying the interactions allowed us to identify the key supramolecular synthons and related elements of the co-former structure, which can serve as tools in the molecular crystal design. [ABSTRACT FROM AUTHOR]

AbstractThe combination of existing drugs or drug–drug interaction enthralls researcher because of their potential applications in multiple diseases and better efficacy. The present work is undertaken to study the interaction between two drugs, Ibuprofen and Paracetamol, using Density Functional Theory and spectroscopic techniques (Infrared and Raman spectroscopy). The molecular modeling of the two drugs indicates their interaction through intermolecular hydrogen bonds (O34-H53-O2 and (O1-H33-O34), which is observed in Natural Bond Orbital and atoms in molecules analysis of the compound (Ibuprofen + Paracetamol). The experimental Raman, Surface Enhanced Raman Spectroscopy and Infrared spectra of the physical mixture (Ibuprofen + Paracetamol) are found close to their computed wavenumbers. The interacting state, that is, Ibuprofen + Paracetamol is optimized using B3LYP/6-31G ++ (d, p) model under density functional theory framework and different computed quantum chemical parameters such as, dipole moment, ionization energy, electron affinity, electrophilicity index, chemical potential, hardness and the Highest Occupied and Lowest Unoccupied Molecular Orbital energies and energy gaps are calculated and compared to the monomer state of the drugs. The lowering of energy gap and increased in dipole moment of combined drug molecules show potency as an effective hybrid drug. The molecular docking study of the combined drug molecule against the 4PH9 receptor shows a better binding affinity with its residues through hydrogen bonding and hydrophobic interaction. [ABSTRACT FROM AUTHOR]

The successful large-scale implementation of hydrogen as an energy vector requires high performance electrodes and catalysts made of abundant materials. Rational materials design strategies are the most efficient means of reaching this goal. Here we present a study on the adsorption of H-atoms onto fcc transition metal surfaces and propose descriptors for the rational design of electrodes and catalysts by means of correlations between fundamental properties of the materials and among other properties, their experimentally measured performance as hydrogen evolution electrodes (HEE). A large set of quantum mechanical modelling data at the DFT level was produced, covering the adsorption of H-atoms onto the most stable surfaces (100), (110) and (111) of: Ag, Au, Co, Cu, Ir, Ni, Pd, Pt and Rh. For each material and surface, a coverage dependent set of minimum energy structures was produced and chemical potentials for adsorption of H-atoms were obtained. Averaging procedures are here proposed to approach modelling to the experiments. Several correlations between the computed data and experimentally measured quantities are done to validate our methodology: surface plane dependent adsorption energies, chemical potentials and experimentally determined surface energies and work functions. We search for descriptors of catalytic activity by testing correlations between the DFT data obtained from our averaging procedures and experimental data on HEE performance. Our methodology allows us to obtain linear correlations between the adsorption energy of H-atoms and the exchange current density (i0) in a HEE, avoiding the volcano-like plots. We show that the chemical potential has limitations as a descriptor of i0 because it reaches an early plateau in terms of i0. Simple quantities obtained from database data such as the first stage electronegativity (χ) as devised by Mulliken has a strong linear correlation i0. With a quantity we denominate modified second-stage electronegativity (χ2m) we can reproduce the typical volcano plot in a correlation with i0. A theoretical and conceptual framework is presented. It shows that both χ and χ2m, that depend on the first ionization potential, second ionization potential and electron affinity of the elements can be used as descriptors in rational design of electrodes or of catalysts for hydrogen systems. [ABSTRACT FROM AUTHOR]

Schiff base labeled as H2L1 was synthesized, which was derived from pyridine-2,6-diamine and 2-hydroxynaphthaldehyde. Types of complexes [ML]Cl2 and [ML(py)2]Cl2, were formed with Co2+, Ni2+, Cu2+, and Zn2+. Additionally, adduct complexes [ML(py)2] were prepared in a ratio of 2:1. Diverse analytical techniques, elemental analyses, (FT-IR, UV-Vis, 1H NMR), conductance measurements, and magnetic susceptibility, were employed to characterize these complexes and adducts. The data acquired validated that the ligands donor atoms act as (ONNO) tetra-dentate bibasic chelating ligands with metal ions. Depending on spectral and magnetic measurements, the suggested shapes of these complexes were reported to be either tetrahedral/octahedral in geometry. Density functional theory (DFT) was used to get some theoretical data about the generated complexes. The data obtained includes the energy of the highest and lowest occupied molecular orbitals (HOMO and LUMO), electron density, ionization potential (IP), electron affinity (EA), electronegativity (En), electrophilicity (), chemical hardness (, and dipole moment (µ). Different characteristics of the complexes have been investigated and explained based on these studied parameters. The molecular docking of target microorganisms of these complexes will be studied. The interaction of DNA gyrase 4ckk with the compounds visualized by LigPlot software. [ABSTRACT FROM AUTHOR]

Recently, oriented external electric fields (OEEFs) have earned much attention due to the possibility of tuning the properties of electronic systems. From a theoretical perspective, one can resort to electronic structure calculations to understand how the direction and strength of OEEFs affect the properties of electronic systems. However, for multi-reference (MR) systems, calculations employing the popular Kohn–Sham density functional theory with the traditional semilocal and hybrid exchange–correlation energy functionals can yield erroneous results. Owing to its decent compromise between accuracy and efficiency for MR systems at the nanoscale (i.e., MR nanosystems), in this study, thermally assisted occupation density functional theory (TAO-DFT) is adopted to explore the electronic properties of n-acenes (n = 2–10), containing n linearly fused benzene rings, in OEEFs, where the OEEFs of various electric field strengths are applied along the long axes of n-acenes. According to our TAO-DFT calculations, the ground states of n-acenes in OEEFs are singlets for all the cases examined. The effect of OEEFs is shown to be significant on the vertical ionization potentials and vertical electron affinities of ground-state n-acenes with odd-number fused benzene rings. Moreover, the MR character of ground-state n-acenes in OEEFs increases with the increase in the acene length and/or the electric field strength. [ABSTRACT FROM AUTHOR]

Mucormycosis is a severe fungal infection which mainly caused by filamentous fungi of the Absidia sp., Rhizopus sp., Cunninghamella sp, Mucor sp., and Rhizomucor sp. Moreover, the pandemic of the SARS-CoV-2 virus expands the need to interfere with spread of the airborne respiratory infections. Accordingly, developing cutting-edge solutions to restrict and/or prevent air contamination by infectious microbes are very warranted. The current work aims to prepare biocidal La-nano complex treated filters and assess their anti-fungal capacity against 20 Rhizopus oryzae, 10 Candida albicans, and 11 Aspergillus fumigatus. These fungi were isolated from the inside parts of the air conditioning systems in the rehabilitation rooms for COVID-19 patients. The obtained results demonstrated that the prepared were able to significantly decrease the invading microbes and eradicate Rhizopus, Aspergillus, Mucor, Candida albicans isolates at 0.64 mg/ml concentration. DFT study compares the electronic properties and reactivity of a ligand in its uncoordinated form with its lanthanum complex. The ligand exhibits lower binding energy, ionization potential, electron affinity, absolute electronegativity, and chemical potential when coordinated with lanthanum. In contrast, the lanthanum complex has a smaller energy gap, absolute hardness, and global softness. [ABSTRACT FROM AUTHOR]

Diamond has an ultrawide bandgap with excellent physical properties, such as high critical electric field, excellent thermal conductivity, high carrier mobility, etc. Diamond with a hydrogen-terminated (H-terminated) surface has a negative electron affinity (NEA) and can easily produce surface electrons from valence or trapped electrons via optical absorption, thermal heating energy or carrier transport in a PN junction. The NEA of the H-terminated surface enables surface electrons to emit with high efficiency into the vacuum without encountering additional barriers and promotes further development and application of diamond-based emitting devices. This article reviews the electron emission properties of H-terminated diamond surfaces exhibiting NEA characteristics. The electron emission is induced by different physical mechanisms. Recent advancements in electron-emitting devices based on diamond are also summarized. Finally, the current challenges and future development opportunities are discussed to further develop the relevant applications of diamond-based electron-emitting devices. [ABSTRACT FROM AUTHOR]

The present work provides Potential Energy Curves (PECs) of both cyano radical CN and cyanide anion ${\rm CN}^{-}$ CN − up to the third asymptote of dissociation out of ab initio calculations. The [MRCI+Q] method is the level of theory used here and we have associated it with the Dunning basis set AV6Z (Augmented correlation-consistent polarised Valence sextet Zeta) for geometry optimisation of our systems. Electronic configurations of the states of the two species were explored and based on these configurations and the relative positions of the PECs of ${\rm CN}^{-}$ CN − against those of the neutral radical CN, stable and metastable states have been found and exhibited. The calculated electron affinity here that proves itself to be positive and the position of the ${\rm X}^{1}\Sigma ^+$ X 1 Σ + state against its corresponding neutral parent state (${\rm X}^{2}\Sigma ^+$ X 2 Σ + ) from which it derives led to confirm that this state is a long-lived and stable ground state of the cyanide anion ${\rm CN}^{-}$ CN − . Spectroscopic constants of both ground and low-lying excited states are calculated and exhibited in this work. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)