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A numerical algorithm based on the probabilistic path integral approach for solving Schrödinger equation has been devised to treat molecular systems without Born–Oppenheimer approximation in the nonrelativistic limit at zero temperature as an alternative to conventional variational and perturbation methods. Using high-quality variational trial functions and path integral method based on generalized Feynman–Kac method, we have been able to calculate the non-Born–Oppenheimer energy for hydrogen molecule for the X 1 Σ g 1 state and hydrogen molecular ion. Combining these values and the value for ionization potential for atomic hydrogen, the dissociation energy and ionization potential for hydrogen molecules have been determined to be 36 113.672(3) cm − 1 and 124 446.066(10) cm − 1 , respectively. Our results favorably compare with other theoretical and experimental results and thus show the promise of being a nonperturbative alternative for testing fundamental physical theories. [ABSTRACT FROM AUTHOR]

The genome—the source of life and platform of evolution—is continuously exposed to harmful factors, both extra- and intra-cellular. Their activity causes different types of DNA damage, with approximately 80 different types of lesions having been identified so far. In this paper, the influence of a clustered DNA damage site containing imidazolone (Iz) or oxazolone (Oz) and 7,8-dihydro-8-oxo-2′-deoxyguanosine (OXOdG) on the charge transfer through the double helix as well as their electronic properties were investigated. To this end, the structures of oligo-Iz, d[A1Iz2A3OXOG4A5]*d[T5C4T3C2T1], and oligo-Oz, d[A1Oz2A3OXOG4A5]*d[T5C4T3C2T1], were optimized at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the aqueous phase using the ONIOM methodology; all the discussed energies were obtained at the M06-2X/6-31++G** level of theory. The non-equilibrated and equilibrated solvent–solute interactions were taken into consideration. The following results were found: (A) In all the discussed cases, OXOdG showed a higher predisposition to radical cation formation, and B) the excess electron migration toward Iz and Oz was preferred. However, in the case of oligo-Oz, the electron transfer from Oz2 to complementary C4 was noted during vertical to adiabatic anion relaxation, while for oligo-Iz, it was settled exclusively on the Iz2 moiety. The above was reflected in the charge transfer rate constant, vertical/adiabatic ionization potential, and electron affinity energy values, as well as the charge and spin distribution. It can be postulated that imidazolone moiety formation within the CDL ds-oligo structure and its conversion to oxazolone can significantly influence the charge migration process, depending on the C2 carbon hybridization sp2 or sp3. The above can confuse the single DNA damage recognition and removal processes, cause an increase in mutagenesis, and harm the effectiveness of anticancer therapy. [ABSTRACT FROM AUTHOR]

Due to its high thermal expansion coefficient and high thermal conductivity, welding of copper and copper alloys is considered difficult and demanding. Activated TIG welding (A-TIG) welding has been widely researched as a welding method for obtaining deeper penetration on various metals. However, A-TIG welding of copper remains unexplored without guidelines on the influence of flux agents and the influence of the applied parameters and achieved mechanical properties in produced welds. In this paper three agents were used as single component fluxes: calcium oxide (CaO), silicon dioxide (SiO2) and sodium carbonate (Na2CO3) for A-TIG welding Cu-ETP sheets. Welds were characterized by visual inspection and macrostructural analysis, also bend testing and tensile strength testing were conducted. Microstructure of the weld with optimal mechanical properties was analyzed by means of Field Emission Gun-Scanning Electron Microscope (FEG-SEM) and also the chemical characterization of the weld was made by means of Energy Dispersive Spectroscopy (EDS). The results showed that the most effective flux used was silicon dioxide. Welds welded with SiO2 showed good results in visual inspection, macrostructure analysis and band test and also have acceptable values of tensile strength. However, oxide inclusions have been found in weld metal in significant percentage which could indicate the possible degradation of electrical conductivity of the material.

We demonstrate the importance of addressing the T vertex and thus going beyond the GW approximation for achieving the energy levels of liquid water in many-body perturbation theory. In particular, we consider an effective vertex function in both the polarizability and the self-energy, which does not produce any computational overhead compared with the GW approximation. We yield the band gap, the ionization potential, and the electron affinity in good agreement with experiment and with a hybrid functional description. The achieved electronic structure and dielectric screening further lead to a good description of the optical absorption spectrum, as obtained through the solution of the Bethe--Salpeter equation. In particular, the experimental peak position of the exciton is accurately reproduced. [ABSTRACT FROM AUTHOR]

The consumption of foods that are high in antioxidant capacity is believed to contribute to good health. Moreover, the addition of highly antioxidant compounds to foods is believed to prevent food deterioration. Among the known antioxidants in food, phenols have been identified as the primary antioxidants. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay is a simple, inexpensive, and rapid method widely used to evaluate the antioxidant capacity. Although the results of the DPPH assay depend on conditions such as the reaction time and concentration, the experimental conditions have not been standardized. Further, previous research that compared the antioxidant capacity determined through the DPPH assay largely focused on the differences in the specific substructures of approximately several dozen compounds. In this study, we conducted DPPH assays on 169 phenols under the same experimental conditions and summarized the correlation between their structures and activity. This DPPH assay study is the first single-laboratory investigation of the largest number of components in terms of their Trolox equivalent antioxidant capacities. Further, the analysis method was reproduced in an interlaboratory collaborative study, enabling its application in the reproduction and comparison of measurements in other laboratories. [ABSTRACT FROM AUTHOR]

Determining the absolute band edge positions in solid materials is crucial for optimising their performance in wide‐ranging applications including photocatalysis and electronic devices. However, obtaining absolute energies is challenging, as seen in CeO2, where experimental measurements show substantial discrepancies in the ionisation potential (IP). Here, we have combined several theoretical approaches, from classical electrostatics to quantum mechanics, to elucidate the bulk and surface contributions to the IP of metal oxides. We have determined a theoretical bulk contribution to the IP of stoichiometric CeO2 of only 5.38 eV, while surface orientation results in intrinsic IP variations ranging from 4.2 eV to 8.2 eV. Highly tuneable IPs were also found in TiO2, ZrO2, and HfO2, in which surface polarisation plays a pivotal role in long‐range energy level shifting. Our analysis, in addition to rationalising the observed range of experimental results, provides a firm basis for future interpretations of experimental and computational studies of oxide band structures. [ABSTRACT FROM AUTHOR]

A series of novel triazolothiadiazolethione and triazolothiadiazine appended indolo[3,2-c]isoquinoline-5-one were designed, synthesized, and validated by IR, 1H, 13C NMR, and mass spectroscopy strategies. All compounds are determined by their DFT investigations with B3LYP/def2-TZVP basis set level, ionization potentials, and electron affinities at vertical (IPv and EAv) and adiabatic parameters (IPA and EAA). Compound 3a has demonstrated the greatest values for these parameters. The compounds' HOMO-LUMO (FMOs) and MEP maps were performed. The optimized structure of the compounds was estimated in global hardness, softness, global electrophilicity, and dipole moment. To find new drug candidates, different in vitro biological activities were implemented employing antimicrobial activity: Gram-negative bacteria were significantly suppressed by compound 4a, whereas gram-positive bacteria were strongly inhibited by compounds 3c and 3a has significant antifungal and anticancer effects. Compound 4b is profoundly antioxidant with IC50 value of 8.74 ± 1.93 µg/mL and MIC value of 0.25 µg/mL for antituberculosis properties. Thereafter, all of the compounds were subjected to e-pharmacophore approach to molecular docking studies. Compound 4a exhibited the best docking score (−8.458 kcal/mol) and docking interactions with active binding sites of 1TL8 receptor. [ABSTRACT FROM AUTHOR]

The semiempirical quasi-classical method of approximation of the ionization potentials used earlier for multiply charged ions of the elements with medium and high atomic number Z is applied to ions of elements with atomic numbers in the range of and number of electrons in the range of . The discovered simple trends allow using a relatively accurate (to within 1–2%), based on two small tables, polynomial approximation of the available and lacking data on the ionization potentials in the NIST tables for all multiply charged ions in the atomic-number range under consideration. An improvement in the applicability conditions of the quasi-classical approximation with increase in the atomic number is demonstrated. [ABSTRACT FROM AUTHOR]

A detailed computational analysis of acridine derivatives viz. acridone, 9-amino acridine hydrochloride hydrate, proflavin, acridine orange and acridine yellow is done in terms of conceptual density functional theory (CDFT). CDFT-based global descriptors—ionization potential, electron affinity, HOMO–LUMO gap, hardness, softness, electronegativity and electrophilicity index of acridine derivatives for ground state as well as excited state are estimated with the help of different hybrid functionals B3LYP/6-31G (d, p), B3LYP/6-311G (d, p), B3LYP/DGDZVP and B3LYP/LANL2DZ. Acridine derivatives show higher values of ionization potential and electron affinity in excited state as compared to ground state, indicating that these compounds are willing to accept electrons in excited state rather than donating electron. Acridone shows the maximum HOMO–LUMO energy gap in ground and excited state which implies that one-way electron transfer is most feasible with this compound. Our computed results emphasize the pronounced electron acceptor behaviour of the acridine derivatives in the excited state which has already been experimentally verified. It is observed that the trend in the computed values of the descriptors is not much improved on refinement of the basis set. [ABSTRACT FROM AUTHOR]

Here, the capacity of various nanocages (C70, Al35N35, Si52, B26N26, Ge60 and B30P30) as anodes in batteries is calculated. Here, the novel materials (Al35N35, B26N26 and B30P30) with high performances and efficiency as anodes to use in batteries are proposed. The Vcell and CTheory of various nanocages (C70, Al35N35, Si52, B26N26, Ge60 and B30P30) as anode in batteries are calculated. The obtained Vcell and CTheory are compared by those values of various nano-compounds, metals and metal oxides as anodes in batteries. The Vcell of Al35N35 and B30P30 nanocages as anode in batteries (1.68 to 2.11 V) are higher than metals and metal oxides and C70, Si52 and Ge60 nanocages. The CTheory of Al35N35 and B30P30 nanocages (548.8 to 808.8 mAh/g) are higher than metals and metal oxides and C70, Si52 and Ge60 nanocages. Here, the Al35N35 and B30P30 are proposed as acceptable anodes in batteries with higher cell voltage and capacity than other metals and metal oxides. [ABSTRACT FROM AUTHOR]

We present nonrelativistic frozen-core and fully-correlated configuration interaction calculations for the ground and lowest excited terms of N+(³P and ¹D) and N(4So and 2Do) belonging to the 2s22pn configuration with n = 2 and n = 3 for N+ and N, respectively. Both the a priori selected configuration interaction with truncation energy error and configuration interaction by parts techniques are employed to manage the wave function expansion and to handle the configuration interaction eigenvalue problem, respectively. Systematic comparisons between the frozen-core and fully-correlated configuration interaction energies and the corresponding excitation energies and the related ionization potential convergence with respect to the configuration interaction excitation level are reported. Comparison of our results for the total nonrelativistic energies, excitation energies, and ionization potential displays good improvement over previous theoretical results and very good agreement with the experiment. [ABSTRACT FROM AUTHOR]

Here we introduce a methodology for calculating vertical detachment energies (VDE) and vertical ionization energies (VIE) of anionic and neutral chromophores in aqueous environment. The proposed method is based on the extended multiconfigurational quasidegenerate perturbation theory coupled to the explicit treatment of solvent effects in the frame of the effective fragment potential method. We show that the solvent polarization contribution must be considered for getting accurate quantitative estimations of VDEs and VIEs. The calculated values of VDE for phenolate (7.3 eV) and VIE for phenol (7.9 eV) in aqueous environment are in good agreement with the experimental results obtained using X-ray and multiphoton UV photoelectron spectroscopy. Our approach will be useful for studying processes of photoinduced electron transfer from anionic as well as neutral biological chromophores in aqueous solution. [ABSTRACT FROM AUTHOR]

The consumption of foods that are high in antioxidant capacity is believed to contribute to good health. Moreover, the addition of highly antioxidant compounds to foods is believed to prevent food deterioration. Among the known antioxidants in food, phenols have been identified as the primary antioxidants. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay is a simple, inexpensive, and rapid method widely used to evaluate the antioxidant capacity. Although the results of the DPPH assay depend on conditions such as the reaction time and concentration, the experimental conditions have not been standardized. Further, previous research that compared the antioxidant capacity determined through the DPPH assay largely focused on the differences in the specific substructures of approximately several dozen compounds. In this study, we conducted DPPH assays on 169 phenols under the same experimental conditions and summarized the correlation between their structures and activity. This DPPH assay study is the first single-laboratory investigation of the largest number of components in terms of their Trolox equivalent antioxidant capacities. Further, the analysis method was reproduced in an interlaboratory collaborative study, enabling its application in the reproduction and comparison of measurements in other laboratories.

During the oxidation of hydrocarbons using hydrogen peroxide solutions, the evolution of gaseous oxygen is a side and undesirable process, in which the consumption of the oxidizer is not associated with the formation of target products. Therefore, no attention is paid to the systematic study of the chemical composition of the gas and the mechanisms of its formation. Filling this gap, the authors discovered a number of new, previously unidentified, interesting facts concerning both gas evolution and the oxidation of hydrocarbons. In a 33% H2O2/Cu2Cl4·2DMG/CH3CN system, where DMG is dimethylglyoxime (Butane-2,3-dione dioxime), and is at 50 °C, evidence of significant evolution of gaseous hydrogen, along with the evolution of gaseous oxygen was found. In the authors' opinion, which requires additional verification, the ratio of gaseous hydrogen and oxygen in the discussed catalytic system can reach up to 1:1. The conditions in which only gaseous oxygen is formed are selected. Using a number of oxidizable hydrocarbons with the first adiabatic ionization potentials (AIPs) of a wide range of values, it was found that the first stage of such a process of evolving only gaseous oxygen was the single electron transfer from hydrogen peroxide molecules to trinuclear copper clusters with the formation, respectively, of hydrogen peroxide radical cations H2O2•+ and radical anions Cu3Cl5•− (AIP = 5 eV). When the conditions for the implementation of such a single electron transfer mechanism are exhausted, the channel of decomposition of hydrogen peroxide molecules into gaseous hydrogen and oxygen is switched on, which is accompanied by the transition of the system to an oscillatory mode of gas evolution. In some cases, the formation of additional amounts of gaseous products is provided by the catalytically activated decomposition of water molecules into hydrogen and oxygen after the complete consumption of hydrogen peroxide molecules in the reaction of gaseous oxygen evolution. The adiabatic electron affinity of various forms of copper molecules involved in chemical processes is calculated by the density functional theory method. [ABSTRACT FROM AUTHOR]

Two-color two-step resonance ionization spectroscopy of neodymium (Nd) was performed to identify more than 120 even-parity autoionizing levels and their candidate J -values. The analysis of the observed autoionizing Rydberg series yielded a value of 44,560.11 (43) stat (2) sys cm−1 as a more accurate ionization potential of Nd. The saturation method was used to measure the transition cross-sections for some intense ionization transitions. From the measured cross-sections, the ionization efficiencies of some two-step ionization schemes were evaluated using the scheme cross-section formula to obtain several promising schemes. [Display omitted] • To determine efficient two-step ionization schemes of Nd, spectroscopic study was performed. • Single-color multiphoton transitions potentially interfering with two-step spectra were identified, • Many ionization spectra were measured to explore intense ionization transitions. • Transition cross-sections were determined from the saturation of the ion yield with intense laser light. • Ionization efficiencies were evaluated based on the scheme cross-section for some promising schemes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-loaded hydroxylated g-C 3 N 4 was prepared by the facile impregnation method. • Co(IV) O exhibits notably higher steady-state concentration than ROS. • Co(IV) O showed high reactivity toward electron-rich pollutants. • Co(IV) O was highly resistant to the inhibitory effect of the complex water matrix. Understanding of the selectivity of high-valent cobalt-oxo species (Co(IV) O) toward diverse organic pollutants with different characteristics in the presence of background constituents remains limited. Here, we prepared Co-loaded hydroxyl group-grafted graphitic carbon nitride (Co-OHCN) using a facile method for the effective formation of Co(IV) O. The role of the hydroxyl group in anchoring Co ions was investigated using several characterization methods (TEM, XRD, FT-IR, and XPS). Co-OHCN exhibited superior efficiency in degrading 4-chlorophenol (4-CP) (98.0 % ± 0.3 %) within 15 min of peroxymonosulfate (PMS) activation reaction. In the Co-OHCN/PMS system, Co(IV) O had the highest steady-state concentration ([Co(IV) O] = 1.40 × 10−10 M), significantly exceeding that of other reactive oxygen species (ROS) ([SO 4 −] = 9.22 × 10−13 M, [OH] = 1.82 × 10−13 M). The dominant role of Co(IV) O in 4-CP degradation was further revealed through scavenger tests, probe methods, and electrochemical analysis. Additionally, the anti-interference of Co(IV) O in the degradation of electron-rich organic substrates to background constituents (NOM and halide ions) was systemically validated using three organic pollutants with different ionization potential values (diclofenac, 4-CP, and benzoic acid). This study provides insight into an efficient strategy for Co(IV) O -mediated pollutant elimination and organic substrate-dependent selectivity of Co(IV) O during water decontamination. [ABSTRACT FROM AUTHOR]

Correlations between bond lengths d and the first ionization potentials of atoms and molecules are established on the basis of experimental data. Functional dependences are obtained for the series of compounds EX3 (E = N, P, As, Sb; X = F, Cl, Br, I) when Х or E are substituted. The difference between dependences with varied E or Х are explained by the differing effects on electron pairs of ion E3−. A way of estimating the values of ion radii RE for the elements N, P, As, and Sb is proposed. Interdependences of the values of radii of ions, their dipole moments, and refractions are discussed. The effect substituents X have on the values of radii RE is shown. The values of radii RE(3−) are evaluated for spherically symmetric ions. Linear dependences of radii RE(3−) and ionization potentials of the corresponding ions E3− and atoms of inert gases on their effective charges are established. [ABSTRACT FROM AUTHOR]

This paper continues the study of the properties of the graphene lattice based on the model of a hydrogen-like atom. The relevance of this topic is not fading away due to the not fully understood mechanism of the conductivity of such fine carbon structures and the processes of emission from their surface. To describe the properties of the lattice, we use a modification of the Brandt–Kitagawa approach with screened ions, which we proposed earlier. In the cold lattice approximation, this model assumes that three valence atoms oriented along bond lines belong to the screening shell of the ion. And only one valence electron determines the ground state of the lattice atom and the inhomogeneous angular distribution of its field. In this study, it is proposed to take into account the Coulomb interactions of electrons in the outer shell of an atom with its own ion and its nearest environment. For this, a modification of the electron density distribution of the shielding shell is developed, taking into account its Coulomb interaction with an electron of a hydrogen-like atom. The problem of the parameters of the ground state of a lattice atom is solved numerically using a variational approach. In the numerical experiments, the parameters of the interaction of a weakly bound electron with an ion are obtained. It is also shown that, for an isolated carbon atom, taking into account the Coulomb interaction of an electron with the shielding shell of an ion makes it possible to accurately calculate the ionization potential of the ground state. The proposed numerical technique leads to adequate results for the calculation of the ionization potential for all light atoms from Li to Ne. [ABSTRACT FROM AUTHOR]

Some molecules in nature have a positive or negative charge. One such molecule is acetylcholine. Acetylcholine is a positively charged molecule that is responsible for Alzheimer's disease. This study evaluated acetylcholine through six simple molecules based on the ionization potential and the HOMO-LUMO gap obtained from the density functional theory calculation. The calculation results showed that the ionization potential and the HOMO-LUMO gap could explain the stability of acetylcholine and the six other molecules. As a result, acetylcholine has the same properties as five other simple molecules. Meanwhile, one other molecule has the opposite properties to acetylcholine. [ABSTRACT FROM AUTHOR]

Substantial neutral atoms can tunnel to excited states in an intense laser field and subsequently generate coherent emission through free induction decay. We experimentally observe an enhanced coherent emission in the harmonic slightly below the threshold, which is consistent with the free induction decay of Rydberg states produced by the frustrated tunnelling ionization (FTI) process. We further find that the intensity of the coherent emission significantly depends on the chirp of laser pulses. The simulations based on the strong field approximation model show that laser chirp affects the probability that the returned electrons recombine to the Rydberg states. Our result shows that coherent emission can be controlled by laser chirp, which facilitates understanding the dynamics of the Rydberg atom and coupling mechanism between the below-threshold harmonics and atomic energy level. In addition, the coherent below-threshold FTI emission we observed has small divergence which is good for EUV light source applications.

We present a benchmark investigation on the performance of various approximate EOM‐CCSD methods for the ionization potential and electron affinity of the genetic material subunits. Our test set consists of 22 molecules, and the canonical EOM‐CCSD method has been used as the reference. Our study shows that the accuracy of approximate methods varies largely for different quantities. However, the pair natural orbital (PNO) based EOM‐CCSD method gives a proper balance between computational cost and accuracy, more suitable than the methods based on perturbative approximation to study properties related to ionization and electron attachment to genetic materials. [ABSTRACT FROM AUTHOR]

Theoretical calculations based on the Diracâ€"Coulombâ€"Breit relativistic coupled cluster method have been carried out for the electron affinities and ionization potentials (IPs) of the superheavy element nihonium (Nh) and its lighter homologues In and Tl. The In and Tl calculations are in agreement with measurement within uncertainties. For Nh, where experiment is yet unknown, we predict the IP of 7.569(48) eV and electron affinity of 0.776(30) eV. [ABSTRACT FROM AUTHOR]

Impurities of different chemical elements inevitably emerge during the preparation of semiconductor nanostructures or are intentionally added to change their transport and optical properties. Most impurities in a bound state can have two or more electrons, rather than one electron. In this case, interelectronic correlations enabling the double photoionization of an impurity atom, one of fundamental reactions, start to play an important role. The aim of the present work was to calculate the first ionization potential of a two-electron impurity center in a semiconductor quantum well by the variation method, as well as to theoretically study the effect of correlations on the double photoionization spectra of two-electron impurity centers in a multiwell quantum structure. The bond energy and first ionization potential of a two-electron atom were calculated by the variation method where the second ionization potential was taken as an empirical parameter. The expression for the impurity light absorption coefficient was obtained in the dipole approximation taking into account the quantum-well width variance. The zero-radius potential method was generalized to the case of two-electron impurities with zero effective nuclear charge in semiconductor quantum wells. An analytical expression for the first ionization potential of a two-electron impurity center was obtained by the variation method in terms of the semiempirical model. The impurity light absorption coefficient upon the one-photon photoionization of a two-electron impurity in a multiwell quantum structure was calculated in the dipole approximation. It is shown that, due to the spatial restriction in a quantum well in one direction, electronic correlations are enhanced to result in higher threshold values of the second ionization potential than those in quantum dots and, as a consequence, more rigid existence conditions of two-electron impurity states. Also, a decrease in the quantum size effect and an increase in the electronic correlation in multiwell quantum structures compared to quasi-zero-dimensional structures were shown to result in transformation of the absorption curve, which is expressed in an increase in the dip between peaks in the double-humped spectral curve. [ABSTRACT FROM AUTHOR]

Anionic complexes LSi(CatR)2 (L is a chelate N-methyl-N-(acetamido)methyl-C,O group or (2-oxo-1-hexahydroazepinyl)methyl-C,O group; CatR is a substituted catecholate ligand) were studied by quantum chemistry at the PBE0/6-311G(d,p) and RI-MP2/def2-TZVPP levels with inclusion of nonspecific solvation using the PCM model. It was shown that the nature of substituents in the catecholate phenyl ring and the L group weakly influences the geometry of the coordination environment of the silicon atom. The higher the electron-withdrawing effect and the number of substituents in the catecholate ligands, the higher the vertical or adiabatic ionization potentials. It was established that the formation of oxidized forms of the complexes LSi(CatR)2 is characterized by weakening of the Si-O bonds between the silicon atom and the CatR (CatR-2) ligand opposite to the Si-O bond with the group L and by shortening of the Si-O bonds between the silicon atom and the other catecholate ligand (CatR-1). An analysis of the average local ionization energies and a topological analysis of the electron localization function showed the CatR-2 ligand is less sensitive to the interaction with free radicals than CatR-1 due to redistribution of electron density from the region of its oxygen atoms and phenyl ring. [ABSTRACT FROM AUTHOR]

The atomic structure of californium is probed by two-step resonance ionization spectroscopy. Using samples with a total amount of about 2 × 10 10 Cf atoms (ca. 8.3 pg), ground-state transitions as well as transitions to high-lying Rydberg states and auto-ionizing states above the ionization potential are investigated and the lifetimes of various atomic levels are measured. These investigations lead to the identification of efficient ionization schemes, important for trace analysis and nuclear structure investigations. Most of the measurements are conducted on 250 Cf. In addition, the isotope shift of the isotopic chain 249 − 252 Cf is measured for one transition. The identification and analysis of Rydberg series enables the determination of the first ionization potential of californium to E IP = 50 , 666.76 (5) cm − 1 . This is about a factor of 20 more precise than the current literature value. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis of sulfur-substituted boron(III) subphthalocyanines (SubPcs) with cationic axial ligands. Subphthalocyanines were synthesized by a condensation reaction using the corresponding phthalonitriles and boron trichloride as a template. An aminoalkyl group was introduced on the central boron atom; this process was followed by N-methylation to introduce a cationic axial ligand. The peripheral sulfur groups shifted the Q band of SubPcs to a longer wavelength. The cationic axial ligands increased the polarity and enhanced the hydrophilicity of SubPcs. The effect of axial ligands on absorption and fluorescence properties is generally small. However, a further red shift was observed by introducing cationic axial ligands into the sulfur-substituted SubPcs. This change is similar to that in sulfur-substituted silicon(IV) phthalocyanines. The unique effect of the cationic axial ligand was extensively investigated by theoretical calculations and electrochemistry. In particular, the precise oxidation potential was determined using ionization potential measurements. Thus, the results of the present study provide a novel strategy for developing functional dyes and pigments based on SubPcs. [ABSTRACT FROM AUTHOR]

A theoretical assessment of the effects of the OH, NH2 and Br substituents on the properties of 2,2′-bipyridine has been carried out using density functional theory approach. The substituents were found to alter both electronic and structural properties of substituted 2,2′-bipyridine with the inductive and resonance effects playing significant roles. For the relative stability study, an order of ortho > para > meta was predicted for each set of the 2,2′-bipyridine derivatives with the ortho conformers being more stable by 4.62, 6.54 and 2.18 kcal/mol than the meta counterparts of the hydroxo, amino and bromo configurations respectively. On the part of electronic property, the electron donating / withdrawing tendency of the substituents was crucial in making electrons available to the bipyridine system. A general reduction in HOMO – LUMO energy gap was noticed upon substitution with the NH2 substituent having greater effect. Furthermore, the calculated reactivity parameters of the 2,2′-bipyridine were altered by substitution with –OH and –NH2 substituents causing reduction in ionization potential (IP) and absolute electronegativity (χ) while the –Br substituent did otherwise. For the solubility simulation, a more negative ΔGsolution was predicted for the hydroxo and amino derivatives at the para position, but reverse was the case for the bromo counterpart. In the case of the optical property, the range separated Time-dependent (LC-TDDFT) calculation revealed that the shifts in absorption λmax caused by the substitution is both substituent and position dependent.

[Display omitted] Metal-free activation of peroxydisulfate (PDS) for degrading organic pollutants in water has received increasing attention because it can prevent secondary pollution. However, most of the catalysts that are efficient are derived from non-renewable fossil resources, are very expensive and have complex preparation processes. Also, the emerging non-radical mechanism is still unclear. Herein, 3D sucrose-derived N -doped carbon xerogels (NCXs) were synthesized by a simple and sustainable hydrothermal process and then employed as novel metal-free PDS activators to degrade organic pollutants. The structure, composition and performance of NCXs were regulated by changing the carbonization temperature. The sample carbonized at 900 °C (NCX900) exhibited the best catalytic performance, completely removing bisphenol A in 60 min. Quenching experiments and linear sweep voltammograms demonstrated that PDS was activated mainly through an electron-transfer non-radical mechanism. It was found that graphitic N played a critical role in activating PDS. With this non-radical mechanism, the NCX900/PDS system could adapt well to the wide pH range (3–11) and high Cl− concentration; it selectively oxidized organic pollutants with low ionization potentials. This work provides a sustainable approach to the low-cost and efficient metal-free catalysts for wastewater treatment. [ABSTRACT FROM AUTHOR]

We present a high-throughput infrastructure for the automated calculation of molecular properties with a focus on battery electrolytes. The infrastructure is largely open-source and handles both practical aspects (input file generation, output file parsing, and information management) as well as more complex problems (structure matching, salt complex generation, and failure recovery). Using this infrastructure, we have computed the ionization potential (IP) and electron affinities (EA) of 4830 molecules relevant to battery electrolytes (encompassing almost 55,000 quantum mechanics calculations) at the B3LYP/6-31+G∗level. We describe automated workflows for computing redox potential, dissociation constant, and salt-molecule binding complex structure generation. We present routines for automatic recovery from calculation errors, which brings the failure rate from 9.2% to 0.8% for the QChem DFT code. Automated algorithms to check duplication between two arbitrary molecules and structures are described. We present benchmark data on basis sets and functionals on the G2-97 test set; one finding is that a IP/EA calculation method that combines PBE geometry optimization and B3LYP energy evaluation requires less computational cost and yields nearly identical results as compared to a full B3LYP calculation, and could be suitable for the calculation of large molecules. Our data indicates that among the 8 functionals tested, XYGJ-OS and B3LYP are the two best functionals to predict IP/EA with an RMSE of 0.12 and 0.27 eV, respectively. Application of our automated workflow to a large set of quinoxaline derivative molecules shows that functional group effect and substitution position effect can be separated for IP/EA of quinoxaline derivatives, and the most sensitive position is different for IP and EA.

We present a high-throughput infrastructure for the automated calculation of molecular properties with a focus on battery electrolytes. The infrastructure is largely open-source and handles both practical aspects (input file generation, output file parsing, and information management) as well as more complex problems (structure matching, salt complex generation, and failure recovery). Using this infrastructure, we have computed the ionization potential (IP) and electron affinities (EA) of 4830 molecules relevant to battery electrolytes (encompassing almost 55,000 quantum mechanics calculations) at the B3LYP/6-31+G∗level. We describe automated workflows for computing redox potential, dissociation constant, and salt-molecule binding complex structure generation. We present routines for automatic recovery from calculation errors, which brings the failure rate from 9.2% to 0.8% for the QChem DFT code. Automated algorithms to check duplication between two arbitrary molecules and structures are described. We present benchmark data on basis sets and functionals on the G2-97 test set; one finding is that a IP/EA calculation method that combines PBE geometry optimization and B3LYP energy evaluation requires less computational cost and yields nearly identical results as compared to a full B3LYP calculation, and could be suitable for the calculation of large molecules. Our data indicates that among the 8 functionals tested, XYGJ-OS and B3LYP are the two best functionals to predict IP/EA with an RMSE of 0.12 and 0.27 eV, respectively. Application of our automated workflow to a large set of quinoxaline derivative molecules shows that functional group effect and substitution position effect can be separated for IP/EA of quinoxaline derivatives, and the most sensitive position is different for IP and EA.

Background. Impurities of various chemical elements inevitably arise in the process of manufacturing semiconductor nanostructures, or are introduced purposefully to change their transport and optical properties. Moreover, most of impurities can have not one, but two or more electrons in a bound state. In this case, electronic correlations begin to play an important role, due to which one of the fundamental reactions is possible - the process of double photoionization of an impurity atom. The purpose of this research is to calculate the first ionization potential of a two-electron impurity center in a semiconductor quantum well using the variational method, as well as a theoretical study of the effect of electronic correlations on double photoionization spectra of two-electron impurity centers in multi-well quantum structures. Materials and methods. The binding energy and the first ionization potential of a two-electron atom were calculated by the variational method, where the second ionization potential was taken as an empirical parameter. The expression for the coefficient of impurity absorption of light was obtained in the dipole approximation taking into account the dispersion of the width of the quantum wells. Results. The method of the zero-radius potential is generalized to the case of two-electron impurities with an effective nuclear charge equal to zero in semiconductor quantum wells. Within the framework of a semiempirical model, an analytical expression for the first ionization potential of a two-electron impurity center is obtained by the variational method. In the dipole approximation, the coefficient of impurity absorption of light is calculated for the photoionization of a two-electron impurity in a multi-well quantum structure with one photon. Conclusions. It is shown that, due to spatial confinement in a quantum well in one direction, there is an increase in electron correlations, which leads to higher threshold values of the second ionization potential than in quantum dots and, as a consequence, to more stringent conditions for the existence of two-electron impurity states. It was also shown that a decrease in the influence of the quantum size effect and an increase in the electron correlation in multi-well quantum structures as compared to quasi-zero-dimensional structures lead to a transformation of the absorption curve, which is expressed in an increase in the gap between the peaks of the two-humped profile of the spectral curve.

The Covid-19 pandemics caused by SARS-CoV-19, and the inadequacy of targeted medications, compelled scientists to seek new antiviral drugs. We present our current understanding of plant extracts containing polyphenols that inhibit Covid-19. Natural phytochemicals (polyphenols) derived from plants have the potential to establish research using extracts and/or individual compounds in the treatment and prevention of coronavirus. The polyphenolic drugs (antivirus) capable of inhibiting the coronavirus protein, that are vital for infection and virus replication. The benefit of phytochemicals is that they promote patient well-being while causing minimal side effects. To understand the antiviral behavior of isolated phytochemicals 1–6, various molecular descriptors, molecular electrostatic potential (MEP), and frontier molecular orbitals (FMO) were investigated. A systematic analysis of isolated phytochemicals was accomplished then molecular descriptors, docking score, active sites, and FMOs energies were compared to the commonly used drugs recently to treat COVID19, namely favipiravir, remdesivir dexamethasone and hydroxychloroquine. Using a molecular docking technique, we demonstrate for the first time that these plant phytochemicals can be inhibited by the core protease (6LU7) protein of COVID19.

For cilazapril (CLZ), analytical methods based on donor–acceptor phenomenon that are simple, rapid with broad linear dynamic range for the quantification of drug are not available in the literature. Considering the requirement for the methods, in this study, two economic, potent analytical methods based on the complexation of CLZ with π-acceptors, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (CA) were developed, validated, and studied spectrophotometrically. Various analytical data were discussed. The effects of experimental variables were optimized from the results of in silico technique, i.e. Box–Behnken design under response surface methodology. Linear dynamic range was significantly good in the range of 6–60 µg mL−1 and 20–260 µg mL−1 for DDQ and CA methods. Moreover, molecular docking studies corroborated the experimental results. Further, the methods were supplemented by the pharmaceutical and biological application for the quantitative assay of CLZ. Collectively, the results of the reported method of the analysis suggest that the developed approach is simple, sensitive, accurate and precise. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabrication of Cu 2 O/TiO 2 catalyst by electroreduction with varying deposition time. • Reduction in work function and ionization potential with respect to the TiO 2 substrate. • New links between deposition time, electronic properties, and light absorption. • Valuable methodology for band diagram tracing from UPS spectra. Among the electronic properties, the positions of the electronic band edges and the work function are essential parameters for determining the potential of a photocatalyst and its ability to function in a solar conversion system. A novel type of photocatalysts, called direct Z-schemes, possesses many advantages over conventional heterojunctions, which all benefit the catalytic performance under solar light. As oxidation and reduction reactions are greatly affected by the electrical characteristics of the material, ultraviolet photoelectron spectroscopy (UPS) is a powerful tool to determine and quantify important electronic parameters of previously fabricated TiO 2 ‖Cu 2 O junctions. TiO 2 nanotubes modified with Cu 2 O nanoparticles exhibit a reduction in the value of the work function (WF = 3.67 ± 0.01 eV) and ionization potential (IP = 6.01 ± 0.04 eV) with respect to the TiO 2 substrate (WF = 4.29 ± 0.02 eV and IP = 7.65 ± 0.05 eV). By varying the electrodeposition time, an optimized amount of deposited Cu 2 O nanoparticles was proven to reduce the WF and IP to facilitate the excitation of electrons, which could be correlated to the improved absorbance in the visible wavelength range. This work proposes a valuable methodology for band diagram tracing from UPS spectra and provides new insights in the relationship between synthesis, electronic properties and visible light absorption of titania based Z-schemes for photocatalytic applications with a combination of surface sensitive techniques and optical absorption studies. [ABSTRACT FROM AUTHOR]

[Display omitted] • New AZO-TZD derivatives (1–11) were synthesized using CSA as a catalyst. The compounds were studied by molecular docking. • A solvatochromic effects with electron-withdrawing and electron-donating substituent investigated. • Computational analysis of molecular geometry, optoelectronic properties, and ionization potential was conducted. • The role of different solvents, substituents, and the donor and acceptor properties of the synthesized compounds considered. • UV–visible spectrum analysis, shows acceptor–donor-acceptor characteristics resembling an organic field-effect transistor OFETs. Here, new AZO-TZD derivatives (1−11) were synthesized using cellulose sulphuric acid (CSA) as a catalyst to prepare diazonium salts and Knoevenagel condensation to produce final products. The prepared dyes were characterized by various methods including UV–Vis, FT-IR, MS, NMR spectroscopic techniques, X-ray diffraction analysis (XRD) and elemental analysis to perform detailed structure elucidation. Then, in another attempt, solvatochromic absorption was studied using different solvents. Also, the effects of substituent with electron-withdrawing and electron-donating groups at their o -, m -, and p -position were investigated. To access a deeper understanding of molecular properties, computational analysis of molecular geometry, optoelectronic properties, and ionization potential was performed. The purpose of the calculations is to clarify the role of different solvents, substituents and donor and acceptor characteristics of the connected rings in the synthesized compounds. Analysis of the UV–Vis spectrum confirmed that these molecules have acceptor–donor-acceptor characteristics that resemble an organic field effect transistor (OFET). In other efforts to evaluate their use as antibacterial, anticancer and anti-Alzheimer agents and their interaction with four different types of enzymes, such as carotenoid dehydrosqualene synthase (PDB ID: 3ACX, gram-positive), aromatase (PDB Id: 4GL7) and acetylcholinesterase (PDB) Id: 7AIX), through UDP-3-O-Acyl- N -Acetylglucosamine Deacetylase (PDB ID: 5U39, gram-negative) and their anticancer docking calculations were investigated. [ABSTRACT FROM AUTHOR]

A supervised learning model combined with genetic algorithm is proposed to predict charge transfer efficiency of nanodiamonds. The model is chosen among ten models whose parameters are modified by genetic algorithm with ten-fold cross-validation, ensuring the accuracy of model. Generalization ability and reliability are further verified by prediction error and consistency tests of twin nanodiamonds. A hydrogenated surface nanodiamond with low ionization potential and a clean nanodiamond with low electron affinity are designed based on particle swarm optimization. It is further found via SHAP analysis that electron affinity is inhibited by surfaces with a {111} surface below 30 % or a {100} surface above 80 %. Similarly, ionization potential is reduced when the hybrid ratios of sp1 and sp2 are separately greater than 0.501 % or lower than 5.690 %. [Display omitted] [ABSTRACT FROM AUTHOR]

Influence on photocurrent sensitivity of hydrothermally synthesized electrochemically active graphene quantum dots on conjugated polymer utilized for a novel single-layer device has been performed. Fabrications of high-performance ultraviolet photodetector by depositing the polypyrrole-graphene quantum dots (PPy-GQDs) active layer of the ITO electrode were exposed to an Ultraviolet (UV) source with 265 and 355 nm wavelengths for about 200 s, and we examined the time-dependent photoresponse. The excellent performance of GQDs was exploited as a light absorber, acting as an electron donor to improve the carrier concentration. PGC4 exhibits high photoresponsivity up to the 2.33 µA/W at 6 V bias and the photocurrent changes from 2.9 to 18 µA. The electrochemical measurement was studied using an electrochemical workstation. The cyclic voltammetry (CV) results show that the hysteresis loop is optically tunable with a UV light source with 265 and 355 nm at 0.1 to 0.5 V/s. The photocurrent response in PPy-GQDs devices may be applicable to optoelectronics devices.

The functional dependence of the values ​​of the terms and ionization potentials of atoms and/or dimers on the information-energy codes of photons interacting with matter is revealed on the basis of absorption spectra, which characterize the physicochemical properties of matter and represent information of a related type determined by self-consistent codes of the source and receiver of information. The tangential function for the systematization of electronic terms in the informational model of quantization (IMQ) has shown the periodic nature of the functions with self-consistency of the photon codes with the codes of atoms in the Periodic Table of Elements. A hypothesis has been proposed about the "subjective" interaction of a photon with matter; an approximation of the ionization potentials of atoms was carried out on the basis of a unified criterion. Extrapolation of the terms and ionization potentials of dimers showed that all the terms observed in absorption fit into series similar to Rydberg terms, and taking the multiplicity into account, certain of their sums form series with different regression coefficients characterizing the intemers (possible valences of dimers). The information component of the interaction of light and matter has revealed real prospects for the development of a new theory of quantum optics and the systematization of large spectroscopy databases. [ABSTRACT FROM AUTHOR]