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In the title compound, C16H13Cl4N3, the dihedral angle between the benzene rings of the dichlorophenyl and dimethylaniline groups is 50.85 (13)°. The central –N=N– unit shows an E configuration. In the crystal, molecules form parallel layers to the (100) plane by C—H···π and face-to-face π-π [centroid-to-centroid distances = 4.0538 (17) and 4.0537 (17) Å] interactions. These layers are connected by Van der Waals interactions to stabilize the crystal structure. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from Cl···H/H···Cl (36.4%), H···H (23.3%) and C···H/H···C (15.2%) contacts. [ABSTRACT FROM AUTHOR]

Recent progress in studies of Rydberg double-well electronic energy states of MeNg (Me = 12-group atom, Ng = noble gas atom) van der Waals (vdW) molecules is presented and analysed. The presentation covers approaches in experimental studies as well as ab initio-calculations of potential energy curves (PECs). The analysis is shown in a broader context of Rydberg states of hetero- and homo-diatomic molecules with PECs possessing complex 'exotic' structure. Laser induced fluorescence (LIF) excitation spectra and dispersed emission spectra employed in the spectroscopical characterization of Rydberg states are presented on the background of the diverse spectroscopic methods for their investigations such as laser vaporization–optical resonance (LV-OR), pump-and-probe methods, and polarization labelling spectroscopy. Important and current state-of-the-art applications of Rydberg states with irregular potentials in photoassociation (PA), vibrational and rotational cooling, molecular clocks, frequency standards, and molecular wave-packet interferometry are highlighted. [ABSTRACT FROM AUTHOR]

Measurements of the 0–0 hyperfine resonant frequencies of ground-state 85Rb atoms show a nonlinear dependence on the pressure of the buffer gases Ar, Kr, and Xe. The nonlinearities are similar to those previously observed with 87Rb and 133Cs and presumed to come from alkali-metal–noble-gas van der Waals molecules. However, the shape of the nonlinearity observed for Xe conflicts with previous theory, and the nonlinearities for Ar and Kr disagree with the expected isotopic scaling of previous 87Rb results. Improving the modeling alleviates most of these discrepancies by treating rotation quantum mechanically and considering additional spin interactions in the molecules. Including the dipolar-hyperfine interaction allows simultaneous fitting of the linear and nonlinear shifts of both 85Rb and 87Rb in either Ar, Kr, or Xe buffer gases with a minimal set of shared, isotope-independent parameters. To the limit of experimental accuracy, the shifts in He and N2 were linear with pressure. The results are of practical interest to vapor-cell atomic clocks and related devices. [ABSTRACT FROM AUTHOR]

Recent advancements in materials science have shed light on the potential of exploring hierarchical assemblies of molecules on surfaces, driven by both fundamental and applicative challenges. This field encompasses diverse areas including molecular storage, drug delivery, catalysis, and nanoscale chemical reactions. In this context, the utilization of nanotube templates (NTs) has emerged as promising platforms for achieving advanced one-dimensional (1D) molecular assemblies. NTs offer cylindrical, crystalline structures with high aspect ratios, capable of hosting molecules both externally and internally (Mol@NT). Furthermore, NTs possess a wide array of available diameters, providing tunability for tailored assembly. This review underscores recent breakthroughs in the field of Mol@NT. The first part focuses on the diverse panorama of structural properties in Mol@NT synthesized in the last decade. The advances in understanding encapsulation, adsorption, and ordering mechanisms are detailed. In a second part, the review highlights the physical interactions and photophysics properties of Mol@NT obtained by the confinement of molecules and nanotubes in the van der Waals distance regime. The last part of the review describes potential applicative fields of these 1D heterostructures, providing specific examples in photovoltaics, luminescent materials, and bio-imaging. A conclusion gathers current challenges and perspectives of the field to foster discussion in related communities. [ABSTRACT FROM AUTHOR]

In this paper, we propose an approach based on parameter β, which equals the free volume in a unit cell normalized to the van der Waals volume of the molecules. The analysis was carried out within a cluster including two-component crystals [CF1 + CF2], in which one of the components remains constant (CF1) and the other varies (CF2). Linear correlation equations, such as β(CC) = C + D·β(CF2), linking the β(CC) parameter of the two-component crystals with the similar parameter β(CF2) of the single-component crystal for the strictly fixed temperatures were derived on the basis of the crystallographic experimental data. The coefficients of the correlation equations for different clusters were analyzed. A relationship was discovered between the correlation coefficient D and the HYBOT descriptor describing the donor and acceptor interactions with the other molecules. A graphic method was developed for analyzing the β(CC) parameter for the cocrystals belonging to the same cluster relative to the β parameter values of the individual compounds β(CF1) and β(CF2). The correlation equations derived in the study give an opportunity to evaluate the unit cell volume of a hypothetical cocrystal knowing only the crystal structure of a single-component crystal of one of the cocrystal components. [ABSTRACT FROM AUTHOR]

Recent advances in synthetic methods, combined with tip‐induced on‐surface chemistry, have enabled the formation of numerous cyclocarbon molecules. Here, we investigate computationally the experimentally studied C16 and C18 molecules as well as their van der Waals (vdW) complexes with several typical donor and acceptor molecules. Our results demonstrate a remarkable electron‐withdrawing ability of cyclocarbon molecules. The vdW complexes of C16 and C18 exhibit a thermodynamically favorable photoinduced electron transfer (ET) from the donor partner to the cyclocarbons that occurs on a picosecond time scale. The lower reorganization energy of C16 compared to C18 leads to a significant acceleration of the ET reactions. [ABSTRACT FROM AUTHOR]

Recent advances in synthetic methods, combined with tip‐induced on‐surface chemistry, have enabled the formation of numerous cyclocarbon molecules. Here, we investigate computationally the experimentally studied C16 and C18 molecules as well as their van der Waals (vdW) complexes with several typical donor and acceptor molecules. Our results demonstrate a remarkable electron‐withdrawing ability of cyclocarbon molecules. The vdW complexes of C16 and C18 exhibit a thermodynamically favorable photoinduced electron transfer (ET) from the donor partner to the cyclocarbons that occurs on a picosecond time scale. The lower reorganization energy of C16 compared to C18 leads to a significant acceleration of the ET reactions. [ABSTRACT FROM AUTHOR]

Two-dimensional materials have aroused the attention of many scientists due to its remarkable chemical, magnetic, optical, and electronic characteristics. However, the specific interaction mechanism between various amino acids with arsenene surfaces has not been explored. We systematically investigated the interactions of 20 amino acids with arsenene by calculating the adsorption energy, electronic structure, sensitivity, and recovery time using density functional theory with Grimme's dispersion correction. Moreover, applying biaxial strains can drastically change the adsorption energy. For the first time, it was discovered that the arsenene monolayer has strong adsorption specificity, high sensitivity, and short recovery time for amino acid molecules through van der Waals interactions. Our findings indicate that the arsenene may be used as a sensing medium for amino acids. [ABSTRACT FROM AUTHOR]

Spectroscopic properties and potential energy curves of alkali metal (M = Na and K) – rare gas (Rg = He, Ne, Ar, Kr, Xe and Rn) van der Waals molecules in their ground states have been studied in detail using spin-restricted open-shell coupled cluster with single and double excitations and perturbative contribution of connected triple excitations (RCCSD(T)) methods. The core-valence correlation (CV) effect was found to be crucial for M-RG molecules containing heavy rare gas atoms. The electronic energies were corrected for the basis set superposition error (BSSE) using the counterpoise method. Energies were extrapolated to the complete basis set (CBS) limit using a two-point scheme. The permanent electric dipole moments, static electric dipole polarizabilities and long-range dispersion coefficients were also calculated. The computed spectroscopic constants, vibrational levels and rotational constants were reported for M-RG and good agreement with the available experimental and theoretical values were found. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and phenolics are pollutants found ubiquitously in freshwater systems. MPs oftentimes serve as a vector for pollutants across ecosystems and are now being explored as alternative adsorbents for pollutant removal. This strategy would reflect the 'reuse' of an existing waste stream into a potentially useful product while at the same time helping to minimize plastic waste in the marine environment. In this study, the adsorption of phenol onto pristine (Pr-PET), modified (Mod-PET), and aged (Ag-PET) Polyethylene Terephthalate (PET) microplastics was examined experimentally and theoretically. Kinetics, isotherms, and thermodynamics models were used to investigate the adsorption process while Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations were employed to investigate molecular level alterations. The result showed that the Ag-PET MPs had the best removal efficiency due larger surface area and the adsorption occurred in a pseudo-second-order manner, showing that the rate of phenol adsorption is directly proportional to the number of surface-active sites on the surface of PET MPs while the intraparticle diffusion defined rate-limiting step. However, the maximum monolayer adsorption capacity followed Mod-PET (38.02 mg/g) > Ag-PET (8.08 mg/g) > Pr-PET (6.84 mg/g). The adsorption process proceeded spontaneously and thermodynamically favourable. GCMC-MD simulations revealed that PET MPs are capable of successfully adsorbing the phenol molecule through Van der Waals and electrostatic interactions and can be adopted as novel adsorbents for phenol removal in aqueous solutions. [ABSTRACT FROM AUTHOR]

We consider the origin of nonlinear collision shifts for the 0–0 hyperfine transition in alkali/noble-gas systems due to van der Waals molecule formation. Developing a semi-empirical model, we describe the shift as arising from three fundamental interactions: (1) a fractional change in the alkali's valence electron density at the alkali nucleus, η, which affects the hyperfine contact term; (2) a mixing of p-wavefunction character into the alkali ground state (characterized by the probability for p-state character appearing in the perturbed wavefunction ξ12), which gives rise to an electric quadrupole term in the ground-state hyperfine splitting; and (3) an interaction of the alkali's valence electron with the magnetic field produced by molecular rotation, characterized by a magnetic field strength BvdW. In addition to these molecular parameters, the model also depends on the formation rate of van der Waals molecules, kfP2, and the breakup rate of the molecules, kbP, where P is the noble-gas pressure. Fitting the model to the 85Rb/Xe and 87Rb/Xe experimental data of McGuyer and co-workers (and taking previously measured values for kf and BvdW), we find that η = 9 × 10−3, ξ12 = 5 × 10−3, and kb = 2.9×107 s−1/Torr. [ABSTRACT FROM AUTHOR]

Based on theoretical calculations and experimental characterizations, the extraction of heavy oil components using subcritical water (Sub-CW) as an extraction solvent was studied in the temperature range of 250–325 °C. According to theoretical calculations, small-scale polycyclic aromatic hydrocarbons (PAHs) are preferentially dissolved in Sub-CW. Meanwhile, the dissolution of heavy oil molecules with large-scale aromatic structures and heterocyclic rings in Sub-CW is hindered. The increase in temperature reduces the hydrogen bonding force between water molecules and the van der Waals repulsion between Sub-CW and PAHs, promoting the dissolution of PAHs in Sub-CW. Extraction experiments applied in a semi-continuous device confirm that Sub-CW selectively extracts aromatic hydrocarbons from heavy oil. Increasing extraction temperature increases the yield of the extract. The aromatic hydrocarbon content in the extract at 325 °C reaches 80 wt%, which is 27 wt% higher than feedstock value. In addition, the asphaltene content in the extract is reduced from the feedstock value of 14 wt% to 2 wt%. • Sub-CW was used as a property-tunable solvent for extracting heavy oil components. • Sub-CW selectively extracts aromatic hydrocarbons from heavy oil. • The yield and composition of the extract are sensitive to extraction temperature. • Opposite distribution of HSP hinders dissolution of PAHs/hetero-PAHs in Sub-CW. • Destruction of hydrogen bonds promotes dissolution of PAHs/hetero-PAHs in Sub-CW. [ABSTRACT FROM AUTHOR]

Diacetylenedisalicylic acid is a new rigid linker molecule, capable of forming strong chelate bonds with metal cations. Its monosubstituted salts with dimethylamine and sodium form 1D and 2D coordination polymers, whose structures were solved from single crystals, along with the dimethyl ester of diacetylenedisalicylic acid. The structure of the dimethyl ester is characterized by a dense co‐facial π‐stacking of molecules with a dominance of van der Waals interactions between the stacks. The angle between the stack direction and the butadiyne groups does not meet the Enkelmann criterion for polymerization in a crystal. In contrast to the dimethyl ester, both salts have a rigid framework with channels filled with disordered solvent molecules. Photoluminescence spectra of the acid and its dimethyl ester have been studied. Thermal analysis of the acid confirms its high thermal stability to 286°C. The acid and its dimethyl ester are prone to polymerization on further heating followed by 50–52% mass loss, forming an amorphous carbon residue at 1000°C. [ABSTRACT FROM AUTHOR]

We study the role of pairwise long-range interactions in the formation of van der Waals molecules through direct three-body recombination processes A + B + B → AB + B, based on a classical trajectory method in hyperspherical coordinates developed in our earlier works [J. Pérez-Ríos et al., J. Chem. Phys. 140, 044307 (2014); M. Mirahmadi and J. Pérez-Ríos, J. Chem. Phys. 154, 034305 (2021)]. In particular, we find the effective long-range potential in hyperspherical coordinates with an exact expression in terms of dispersion coefficients of pairwise potentials. Exploiting this relation, we derive a classical threshold law for the total cross section and the three-body recombination rate yielding an analytical expression for the three-body recombination rate as a function of the pairwise long-range coefficients of the involved partners. [ABSTRACT FROM AUTHOR]

Non-covalent interactions such as van der Waals interactions and hydrogen bonds are crucial for the chiral induction and control of molecules, but it remains difficult to study them at the single-molecule level. Here, we report a carbene molecule on a copper surface as a prototype of an anchored molecule with a facile chirality change. We examine the influence of the attractive van der Waals interactions on the chirality change by regulating the tip-molecule distance, resulting in an excess of a carbene enantiomer. Our model study provides insight into the change of molecular chirality controlled by van der Waals interactions, which is fundamental for understanding the mechanisms of chiral induction and amplification. The control of molecular chirality is of great interest in stereochemistry and biochemistry. Here, the authors show how to alter the chirality dynamics of a single molecule through tip-induced van der Waals interactions. [ABSTRACT FROM AUTHOR]

By using CCSD(T) and EOM-CCSD methods together with quasirelativistic energy-consistent small-core pseudopotentials and large atom-centered basis sets as well as bond functions, the potential energy curves (PECs) for the ground state and several low-lying singlet excited states of the van der Waals molecular systems between cadmium atom interacting with RG atoms (RG = He, Ne, Ar, Kr, Xe and Rn) are obtained. The dispersion coefficients of ground state for Cd-RG have been computed. And the spectroscopic constants of the bound states of Cd-RG molecules have been calculated, the spectroscopic constants of ground state and C1Π state of Cd-RG complexes are in reasonable agreement with the available theoretical and experimental results; the vertical excitation energies of singlet low-lying excited states are also obtained. And the transition dipole moments (TDMs) of (3)1Σ+-X1Σ+ and (4)1Σ+-X1Σ+ transitions are discussed, which would be helpful to understand the transition properties of Cd-RG complex. Furthermore, frequencies of vibrational transitions, rotational constants, Franck-Condon factors (FCFs) of C1Π-X1Σ+ transition and oscillator strengths of Cd-RG have also been acquired. The present work would be of value to understand on the electronically excited states of Cd-RG molecule, especially the electronic structure and spectroscopic characteristics of the singlet excited states. [ABSTRACT FROM AUTHOR]

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The performance of 24 vdW‐DF functionals were evaluated. The calculated intermolecular interaction potentials for 11 complexes, which conatain O, S, Se, N, P, F, Cl and Br atoms, were compared with CCSD(T)/CBS level potentials to evaluate their accuracy. The performance depends on the choice of vdW‐functional significantly. The vdW‐DF3‐opt1 functional shows the best performance. The deviation ratios of calculated interaction energies of the complexes using the vdW‐DF3‐opt1 functional to CCSD(T) level interaction energies at the potential minima are −6 to 14 %. As a general tendency, the accuracy is improved in the order of vdW‐DF, vdW‐DF2, and vdW‐DF3, but even if they belong to the same group, the accuracy greatly differs depending on each functional. The calculations of hydrocarbon molecules show better performance compared with heteroatom containing molecules in most cases. The calculations using the vdW‐DF3‐opt1 functional and the best dispersion corrected DFT calculations show nearly identical performance. [ABSTRACT FROM AUTHOR]

Using the van der Waals density functional theory, we studied the binding peculiarities of favipiravir (FP) and ebselen (EB) molecules on a monolayer of black phosphorene (BP). We systematically examined the interaction characteristics and thermodynamic properties in a vacuum and a continuum, solvent interface for active drug therapy. These results illustrate that the hybrid molecules are enabled functionalized two-dimensional (2D) complex systems with a vigorous thermostability. We demonstrate in this study that these molecules remain flat on the monolayer BP system and phosphorus atoms are intact. It is inferred that the hybrid FP+EB molecules show larger adsorption energy due to the van der Waals forces and planar electrostatic interactions. The changes in Gibbs free energy at different surface charge fluctuations and temperatures imply that the FP and EB are allowed to adsorb from the gas phase onto the 2D film at high temperatures. Thereby, the results unveiled beneficial inhibitor molecules on two dimensional BP nanocarriers, potentially introducing a modern strategy to enhance the development of advanced materials, biotechnology, and nanomedicine. [ABSTRACT FROM AUTHOR]

Host–guest hybrid (HGH) consisting of p-But-calix[8]arene and fullerene C70 were fabricated with a facial solution deposition method. The as-prepared HGH samples are well periodic arranged in a layer structure, in which the interactions between the guest C70 and host p-Butcalix[8]arene molecules are van der Waals forces. High pressure Raman and UV–Vis absorption spectra studies on the HGH were recorded. Our results show that an orientational related phase transition and a one-dimensional (1D) polymerization of C70 molecules occur at about 2 and 7 GPa at room temperature, respectively. The band gap of the HGH translated synchronously with the change of structure upon compress. We suggest that the molecular confinement in such layer structure of the HGH restricts the polymerization of C70 molecules within a layer, which tunes the phase transition process of C70. This supplies a possible way to design fullerene-based functional materials at suitable conditions. [ABSTRACT FROM AUTHOR]

Pristine graphene is not suitable for hydrogen storage at ambient conditions since it binds the hydrogen molecules only by van der Waals interactions. However, the adsorption energy of the hydrogen molecules can be improved by doping or decorating metal atoms on the graphene monolayer. The doping and decoration processes are challenging due to the oxygen interference in hydrogen adsorption and the clustering issue of metal atoms. To improve the hydrogen adsorption energy in pristine graphene, we have explored the hydrogen storage capabilities of graphene monolayer in the presence of compressive strain. We found that at 6% of biaxial compressive strain, a 4*4*1 supercell of graphene can adsorb 10 H2 molecules above the graphene surface. The average binding energy of H2 for this configuration is found to be −0.42 eV/H2, which is very suitable for reversible hydrogen adsorption. We propose that a 4*4*1 supercell of graphene can adsorb a total number of 20 H2 molecules leading to a high hydrogen uptake of 9.4%. The interaction between orbitals of carbon and hydrogen atoms and the charge transfer process have been studied by plotting the partial density of states and surface charge density plots. The electronic density around the C–C bonds of graphene increases in the presence of compressive strain, due to which hydrogen molecules are strongly adsorbed. [ABSTRACT FROM AUTHOR]

The low solubility of pea protein isolate (PPI) greatly limits its functional properties and its wide application in food field. Thus, this study investigated the effects and mechanisms of cellulose nanocrystals (CNC) (0.1–0.4 %) and CaCl 2 (0.4–1.6 mM) on the solubility of PPI. The results showed that the synergistic effect of CNC (0.3 %) and Ca2+ (1.2 mM) increased the solubility of PPI by 242.31 %. CNC and Ca2+ changed the molecular conformation of PPI, enhanced intermolecular forces, and thus induced changes in the molecular morphology of PPI. Meanwhile, the turbidity of PPI decreased, while surface hydrophobicity, the absolute zeta potential value, viscoelasticity, β-sheet ratio, and thermal properties increased. CNC bound to PPI molecules through van der Waals force and hydrogen bond. Ca2+ could strengthen the crosslinking between CNC and PPI. In summary, it is proposed a valuable combination method to improve the solubility of PPI, and it is believed that this research is of great significance for expanding the application fields of PPI and modifying plant proteins. [Display omitted] [ABSTRACT FROM AUTHOR]

Moisture-induced degradation is an inherent phenomenon at the interface between rubber-modified asphalt and aggregate, moisture ingress through diffusion impairs the integrity of this interface. This study employed molecular simulation to assess the performance of the rubber-modified asphalt and aggregate interface, considering multiple influencing factors such as temperature and loading. Infrared spectroscopy served to validate the alterations in functional groups after moisture exposure. Quantitative metrics, including mean square displacement, interfacial adhesion energy, adsorption energy, radius of gyration, solubility parameter, and molecular orientation, were computed to pinpoint the moisture-induced degradation zones. The findings demonstrated that the maximum moisture diffusion rate subject to various influencing parameters occurred at 298 K and 3 atm, as well as 333 K and 3 atm. Temperature exerted a more profound influence on the rubber-modified asphalt-aggregate interface compared to loading. The strength of hydrogen bonding between moisture and rubber molecules surpassed Van der Waals forces and induction force. Infrared spectroscopy showed that the diffused moisture persisted within the interface. • The moisture-induced degradation zone was successful marked. • The temperature effect on the interface was greater than that of loading. • H-bond force stronger than Van der Waals force and induction force was proposed. [ABSTRACT FROM AUTHOR]

• Deep eutectic solvents are screened to remove water and methanol from dimethyl ether. • VLE data are measured to regress the parameters of the NRTL model. • The interaction mechanisms of systems are revealed at the molecular level. • The industrial-scale process of separation has been established and optimized. This study examines the viability of utilizing deep eutectic solvents for the separation of methanol and water from crude dimethyl ether. To begin with, the COSMO-SAC model is employed to screen various deep eutectic solvents, The results indicate that deep eutectic solvents formed by choline chloride as the hydrogen bond acceptor and glycerol as the hydrogen bond donor exhibit excellent selectivity. Additionally, the non-ideal nature of the system is initially assessed using the σ-profile and excess enthalpy. Subsequently, the vapor–liquid equilibrium data for dimethyl ether /methanol/water and deep eutectic solvents are determined through model predictions and saturation vapor pressure experiments. Furthermore, Quantum computation is used to generate the electrostatic potential surfaces and distribution of extremum points of the van der Waals surface of molecules, explaining the interaction sites between molecules. Molecular dynamics simulations are employed to analyze the spatial distribution functions and radial distribution functions of multi-molecular systems. Lastly, a process flow for the removal of methanol and water from dimethyl ether is established. Under the optimal operating conditions, the combined concentration of methanol and water in dimethyl ether is successfully reduced to below 50 ppm, thus demonstrating the feasibility of this approach. [ABSTRACT FROM AUTHOR]

When the bond lengths of 11 molecules containing van der Waals bonds are optimized by 572 methods and 20 basis sets, it is found that the best mean absolute deviations (MADs) of density-functional theory (DFT) methods are 0.005 Å (shown by APFD/6-311++G**), 0.007 Å (B2PLYPD3(Full)/aug-cc-pVQZ), and 0.010 Å (revDSDPBEP86/aug-cc-pVQZ), while the best MADs of ab initio methods are 0.008 Å (BD(T)/aug-cc-pVTZ) and 0.016 Å (MP4/aug-cc-pVQZ). Moreover, the best MADs calculated by 54 selected methods in combination with 60 other basis sets (such as 6-311++G, 6-31++G(3d′f,3p′d), and UGBS1V++) are not better. Therefore, these bond lengths can be calculated with extremely high accuracy by some special methods and basis sets, and CCSD(T) is also not as good as expected because its best MAD is only 0.023 Å (CCSD(T)/aug-cc-pVQZ). [ABSTRACT FROM AUTHOR]

Basic characteristics of a free-jet supersonic expansion beam are presented along with an estimation of a number of expanding CdAr and ZnAr molecules that are excited in the free-jet in the optical–optical double resonance process. The estimation is demonstrated for laser excitation from the ground, via respective A30+(53P1) or C11(41P1) intermediate, to the E31(63S1) or 11(41D2) Rydberg state of CdAr or ZnAr, respectively. A number of subsequently emitted and collected photons is also predicted. [ABSTRACT FROM AUTHOR]

Three-body recombination, or ternary association, is a termolecular reaction in which three particles collide, forming a bound state between two, whereas the third escapes freely. Three-body recombination reactions play a significant role in many systems relevant to physics and chemistry. In particular, they are relevant in cold and ultracold chemistry, quantum gases, astrochemistry, atmospheric physics, physical chemistry, and plasma physics. As a result, three-body recombination has been the subject of extensive work during the last 50 years, although primarily from an experimental perspective. Indeed, a general theory for three-body recombination remains elusive despite the available experimental information. Our group recently developed a direct approach based on classical trajectory calculations in hyperspherical coordinates for three-body recombination to amend this situation, leading to a first principle explanation of ion-atom-atom and atom-atom-atom three-body recombination processes. This review aims to summarise our findings on three-body recombination reactions and identify the remaining challenges in the field. [ABSTRACT FROM AUTHOR]

In this study, four new piperazinium salts, namely, 4-phenylpiperazin-1-ium 4- ethoxybenzoate monohydrate, C9H9O3⋅C10H15N2⋅H2O (I); 4-phenylpiperazin-1-ium 4-methoxybenzoate monohydrate, C10H15N2⋅C8H7O3⋅H2O (II); 4-phenylpiperazin-1-ium 4-methylbenzoate monohydrate, C10H15N2⋅C8H7O2⋅H2O (III); and 4-phenylpiperazin-1-ium trifluoroacetate 0.12 hydrate, C10H15N2⋅C2F3O2⋅-0.12H2O (IV), have been synthesized. The single-crystal structures of these compounds reveal that all of them crystallize in the triclinic P1 space group and the crystal packing of (I)--(III) is built up of ribbons formed by a combination of hydrogen bonds of type N--H⋯O, O--H⋯O and other weak interactions of type C--H⋯O and C--H⋯, leading to a three-dimensional network. In the crystal of (IV), the cations and the anions are connected by C--H⋯O, N--H⋯O and C--H⋯F hydrogen bonds and by C--H⋯ interactions, forming sheets which in turn interact to maintain the crystal structure by linking through the oxygen atoms of water molecules and van der Waals interactions, giving the whole structure. [ABSTRACT FROM AUTHOR]

• New 3-isopropyl-2,6-diphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one (IPTP) single crystals analysis. • The Hirshfeld surface analysis was employed to examine intermolecular contacts. • Compare the spectral studies of DFT experimental and theoretical and vibrational energy distribution analysis (VEDA) analysis. • Anti-HIV activities were observed for synthesized compounds. • FDA-approved anti-HIV drug of Nelfinavir molecular docking and ADME (Computational study) have been predicted. The 3-isopropyl-2,6-diphenyl-1-(2-(thiophen-2yl)acetyl)piperidin-4-one (IPTP) single crystals were grown by slow evaporation method and the structure is confirmed through FT-IR, 1H NMR, and 13C NMR spectral analyses. Single crystal X-ray diffraction revealed that the title compound having chair conformation of the piperidine ring, with an axial orientation of phenyl rings at C-2 and C-6 positions and an isopropyl group at C-3. Hirshfeld surface analysis was employed to examine intermolecular contacts and strong and weak attractive, repulsive, and van der Waals interactions in the molecule were determined using the reduced density gradient method (RDG). The geometrical parameters obtained through Density Functional Theory are compared with experimental values and also conducted to optimize structural parameters, frontier molecular orbitals (FMOs), and molecular electrostatic potential surface analysis (MEPS). NBO calculations were employed to investigate intermolecular and intramolecular charge movement, as well as the molecule's stability. Vibrational Energy Distribution Analysis (VEDA) software facilitated potential energy decomposition (PED) analysis using FT-IR wave numbers. The title compound molecular docking data were compared with the markedly available FDA-approved anti-HIV drug of Nelfinavir and their results were discussed, ADME analysis studies were discussed concerning FDA-approved anti-HIV drugs, including Nelfinavir, Betulinic Acid, Haloperidol, and Donepezil. [Display omitted] [ABSTRACT FROM AUTHOR]

We investigated ion‐beam (IB)‐treated polyacrylamide (PAM) film as a liquid crystal (LC) alignment layer. Polarized optical microscopy and pretilt angle analysis show the uniform LC alignment status. Atomic force microscopy shows the IB etching effect, and X‐ray photoelectron spectroscopy indicates the formation of carbon–oxygen bonds on the surface, which ensured the uniform alignment of LC molecules via van der Waals forces interaction. The reformed PAM films also had good thermal budgets and optical transparency for the LC system. The IB‐treated PAM films demonstrated stable electro‐optical performances in a twisted nematic LC system. Hence, IB treatment can be an effective method to apply several polymer materials to the LC alignment layer, and IB‐irradiated PAM films have remarkable potential for use in the LC system. [ABSTRACT FROM AUTHOR]

On the basis of examples like this, mathematicians (or mathematics students reading the textbook example) might expect that facts about complex numbers oftentimes reveal the reasons for results exclusively concerning real numbers - results that would otherwise have seemed coincidental. Imaginary coordinates for points of intersection arise when there is no Euclidean triangle with sides of lengths I r i SB 1 sb , I r i SB 2 sb , and I L i , which occurs when I L i > I r i SB 1 sb + I r i SB 2 sb (case (b) in the figure) or I L i < | I r i SB 1 sb HT ht I r i SB 2 sb | (case (c) in the figure). [Extracted from the article]

In this research, a dataset including 206 volatile organic compounds was used to develop quantitative structure–retention relationship models for predicting the retention indices of volatile organic compounds on DB-5 stationary phase. A total of 141 molecules were put in train set to build models and 65 molecules were put in test set to validate models, externally. By using stepwise-multiple linear regression, two descriptors including X1sol (solvation connectivity index chi-1) and AAC (mean information index on atomic composition) were selected to create linear and nonlinear quantitative structure–retention relationship models. Multiple linear regression, epsilon-support vector regression and deep learning-based artificial neural network were used as modeling techniques. All models were validated by calculating several statistical parameters for both train and test sets that show created models have high predictive power. R2 values for the test set of multiple linear regression, epsilon-support vector regression and deep learning-based artificial neural network models were 0.90, 0.94 and 0.94, respectively. Results show the Van der Waals interactions of molecules with methyl groups in DB-5 stationary phase and the electrostatic interactions of atoms with partial negative charge in molecules with the hydrogen atoms of phenyl groups in DB-5 stationary phase are responsible for the separation of volatile organic compounds in DB-5 stationary phase. Finally, these created models were used to predict the retention indices of 694 volatile organic compounds that had no retention index data on DB-5 stationary phase. [ABSTRACT FROM AUTHOR]

The importance of coupled clusters iterative triple and noniterative quadruple, T (Q) , electron excitations on the potential energy surfaces (PESs) of van der Waals molecules is examined for H 2 –CO. The evaluation of this importance is performed by comparing theoretical spectra with experiment. Somewhat surprisingly, although the T (Q) contributions to interaction energies are below 3%, the inclusion of them reduces the error of theory with respect to experiment by an order of magnitude and qualitative agreement of the spectra in some regions is achieved only when they are included. The main reason for these observations is that the T (Q) effects significantly change the anisotropy of the PES. [ABSTRACT FROM AUTHOR]

[Display omitted] The heterodimer, XeAr, is a classic example of a weakly bound van der Waals molecule, which has a variety of accessible bound excited states that exhibit complex interactions. In this study, XeAr has been investigated in the 77,500–81,500 cm−1 region using a combination of Resonance Enhanced Multi-Photon Ionization (REMPI) spectroscopy and Velocity Map Imaging (VMI). By monitoring REMPI and photodissociative product channels across the spectrum, several novel excited states, product channels, excited state symmetries and lifetimes, as well as highly localized perturbations were observed and characterized, including the first VMI study of Ar* dissociating from XeAr Rydberg states accessed by two-photon excitation. In this work we have analyzed 38 vibronic bands representing nine different electronic transitions, and we provide new assignments for two 0 + ← 0 + electronic transitions dissociating to the Xe* 5 d [3/2]0 2 (ca. 80,323 cm−1) and Xe* 5 d [7/2]0 3 (ca. 80,970 cm−1) limits. Several new predissociation product channels were identified at the two- and three-photon levels, including production of Xe* 5 p [5/2] 3 , Xe* 6 s' [1/2]o 1 , Xe* 6 p [1/2] 1 , Ar* 4 p [1/2] 0 , Ar* 4 p '[3/2] 1 , Ar* 4 p '[1/2] 1 , and Ar* 4 p [5/2] 3. Using the multidimensional analysis offered by VMI, we explore interesting photophysics whereby a resonant state that is reached after absorbing two photons can predissociate to yield Xe*, but which also can absorb a 3rd photon, yielding super-excited Ar*Xe that predissociates to Ar* limits. The ground state dissociation energy for XeAr was determined to be D 0 = 114.4 ± 2.7 cm−1, in excellent agreement with previous measurements. [ABSTRACT FROM AUTHOR]

In this study, we aimed to analyze the effects of first and second-generation Bcr-Abl tyrosine kinase inhibitors, imatinib and nilotinib on LPS/IFN gamma activated RAW 264.7 macrophages. Our data revealed that imatinib was less effective on nitrite levels and more toxic on macrophages compared to nilotinib. Therefore, we further analysed the effect of nilotinib on various inflammatory markers including iNOS, COX-2, NFkB, IL-6, p-ERK, p-p38 and p-JNK in LPS/IFN gamma activated RAW264.7 macrophages. Spectrophotometric viability test and Griess assay,western blot, RT-PCR and luciferase reporter assays were used to analyze the biological activity of nilotinib. Our findings revealed that nilotinib decreases nitrite levels, iNOS mRNA, iNOS and p-p38 protein expressions significantly whereas induces IL-6 mRNA and p-JNK protein expressions at particular doses. We did not find significant effect of nilotinib on COX-2, p-ERK and nuclear p65 proteins and NFkB transcriptional activity. In addition, the binding mode of nilotinib to iNOS protein was predicted by molecular docking. According to the docking analyses, nilotinib exhibited hydrophobic interactions between MET349, ALA191, VAL346, PHE363, TYR367, MET368, CYS194, TRP366 residues at the binding pocket and the molecule as well as van der Waals interactions at specific residues. In conclusion, our results reveal that, in addition to its anticancer activity, nilotinib can exhibit immune modulatory effects on macrophages through its effects on iNOS, IL-6, p-p38 and p-JNK. [Display omitted] • Imatinib exhibits higher toxicity than Nilotinib in Mo and M1 RAW 264.7 macrophages. • Nilotinib inhibits iNOS at both mRNA and protein level in M1 RAW 264.7 macrophages. • Nilotinib exacerbates p-JNK and inhibits p-p38 activation in M1 macrophages. • Nilotinib does not significantly effect p-ERK, NFkB and COX-2 in M1 macrophages. • Nilotinib exhibits hydrofobic and van der waals interactions with iNOS. [ABSTRACT FROM AUTHOR]

Graphene based van der Waals heterostructures (vdWHs) have gained substantial interest recently due to their unique electrical and optical characteristics as well as unprecedented opportunities to explore new physics and revolutionary design of nanodevices. However, the heat conduction performance of these vdWHs holds a crucial role in deciding their functional efficiency. In-plane and out-of-plane thermal conduction phenomena in graphene/2D-SiC vdWHs were studied using reverse non-equilibrium molecular dynamics simulations and the transient pump-probe technique, respectively. At room temperature, we determined an in-plane thermal conductivity of ~ 1452 W/m-K for an infinite length graphene/2D-SiC vdWH, which is superior to any graphene based vdWHs reported yet. The out-of-plane thermal resistance of graphene → 2D-SiC and 2D-SiC → graphene was estimated to be 2.71 × 10−7 km2/W and 2.65 × 10−7 km2/W, respectively, implying the absence of the thermal rectification effect in the heterobilayer. The phonon-mediated both in-plane and out-of-plane heat transfer is clarified for this prospective heterobilayer. This study furthermore explored the impact of various interatomic potentials on the thermal conductivity of the heterobilayer. These findings are useful in explaining the heat conduction at the interfaces in graphene/2D-SiC vdWH and may provide a guideline for efficient design and regulation of their thermal characteristics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The MD + DFT complementarity method is used. • The adsorption activation behavior of activated molecules on the surfaces of the six catalysts occurs in the first adsorption layer. • The electrostatic interaction between catalyst and activated molecules and van der Waals interaction have significant effects on the adsorption process of both, and the electrostatic interaction is greater than the van der Waals interaction. • Compared with other heteroatom-doped graphene, BGR and NGR have better catalytic properties, in which BGR has better catalytic activation properties for H 2 O 2 , while NGR has better catalytic activation properties for PMS. • It is speculated that -BC 2 O and -NC 2 functional groups are the main functional regions of H 2 O 2 activation by BGR and PMS activation by NGR, respectively. As an green and efficient metal-free catalyst, heteroatom-doped graphene has gradually become a research topic in the catalytic field, but the active sites and mechanisms of the catalytic reactions are still not thorough enough. In this paper, the adsorption-activation properties of two activated molecules, H 2 O 2 and peroxymonosulfate (PMS), on graphene (GR) and heteroatom (N, P, B, Si, F) doped graphene were investigated by means of computational methods. Molecular dynamics (MD) simulation results showed that the adsorption activation process of activated molecules on the surface of the six catalysts occurs in their first adsorption layer, in which B-doped graphene (BGR) has better catalytic activation performance for H 2 O 2 , while N -doped graphene (NGR) has better catalytic activation performance for PMS. Density function theory (DFT) revealed that the lowest molecular orbital gap of H 2 O 2 at -BCO 2 (0.691 eV), PMS at -NC 2 has the lowest gap (0.432 eV). It is inferred that -BCO 2 and -NC 2 functional groups are the main functional regions of H 2 O 2 activation by BGR and PMS activation by NGR, respectively. This work provides useful guidance for the design and optimization of high-performance metal-free catalysts, and the realization of green remediation for wastewater in the electrocatalytic oxidation process. [ABSTRACT FROM AUTHOR]

• The Sn/Pd(100) electrode exhibits NO 3 RR activity when the pH is below 3.8. • The form of Sn2+ (pH < 3.8) promotes NO 3 − adsorption on Sn site. • Combination of Sn and Pd reduces the LUMO energy of adsorbed nitrate molecule. • Protonation of NO 2 − is crucial to support its reduction on the surface of Pd(100). Nitrate is a common pollutant in groundwater and endangers drinking water safety. The electrocatalytic nitrate reduction using tin-modified palladium electrode (Sn/Pd) provided a promising alternative for nitrate removal. However, the pH effect on the nitrate reduction activity of Sn/Pd and its mechanistic insights are still unclear. In this study, Sn/Pd(100) single crystalline electrodes were used as a model electrode to understand the pH effect on its nitrate and nitrite reduction activity and mechanism. Sn/Pd(100) electrodes showed the nitrate reduction activity at pH < 3.8. DFT calculations suggest that Sn2+ site can be found on Pd(100) at pH < 3.8 and promote nitrate adsorption. The copresence of Sn and Pd sites can reduce the LUMO energy of the adsorbed nitrate molecule and decrease the van der Waals electrostatic potential of the O-N bond, which promotes electron injection and protonation to nitrate. At pH > 3.8, on the other hand, the formation of Sn(OH)+ or Sn(OH) 2 can inhibit the adsorption of NO 3 − on Sn atoms, resulting in the disappearance of the electrocatalytic activity. Sn atomic sites mainly promote the reduction step of NO 3 − → NO 2 −, and the subsequent NO 2 – reduction reaction occurs on Pd sites. The protonation of NO 2 – was crucial to the nitrite reduction on Pd(100) surface. The findings in this study would be useful to develop highly active electrocatalysts based on Sn and Pd materials for the nitrate reduction. [Display omitted] [ABSTRACT FROM AUTHOR]

The helical structure of V‐amylose offering a superior encapsulation affinity compared with the other polysaccharides, especially toward the amphiphilic or hydrophobic molecules; in addition to providing a higher resistance toward enzymatic hydrolysis support its applications as a potential drug delivery vehicle. Mainly, the glycosidic linkages and –CH2– groups forming the hydrophobic cavity of V‐amylose helix, and the glycosyl hydroxyl groups constituting its hydrophilic periphery promote the loading of a diverse range of molecules via van der Waals forces and hydrogen bonding interactions. These properties enable a high‐loading efficiency, targeted delivery, and controlled release of the cargo drug molecules by V‐amylose. Besides, V‐amylose presents characteristics of an ideal drug delivery system, such as biocompatibility, physiological benevolence, nonimmunogenicity, and biodegradability. The V‐amylose polysaccharide chains fold into left‐handed single helix comprising of six glucose units in each turn having a pitch height of 7.91–8.17 Å. These structural features of V‐amylose differentiate it from the parent amylose polysaccharide and enable the accommodation and nanoencapsulation of a wide range of therapeutics in the former. The tightly packed helical structure of V‐amylose provides extraordinary resistance toward digestion by amylase compared with the linear polysaccharides, which supports the application of V‐amylose as controlled drug release systems. The activity of the amylase enzyme produced by salivary glands, pancreas, gastrointestinal tract, and gut microbiota on amylose‐based drug delivery vehicles promote enzyme‐sensitive controlled oral and colon‐specific release of the encapsulated drug. The single helical V‐amylose with hydrophobic core and hydrophilic periphery forms inclusion complexes that improve the absorption and permeation of drugs having a high clogP index. The present commentary highlights the distinguished features of V‐amylose as an imminent drug delivery system. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • (GaAs, Graphene, InSe)-(WS 2 , MoS 2) van der Waals heterojunctions. • Building relationship between atomic coordination density and surface strain. • Interfacial atomic cohesive energy and the bond energy density vary. Abstract Density functional theory (DFT) calculations have revealed the essential nature of bond relaxation and electronic reconfiguration in (GaAs, Graphene, InSe)-(WS 2 , MoS 2) layered heterojunctions. The bandgap lies within the range 0.01 ∼ 1.0 eV, which may be suitable for photocatalytic applications. We have also established a relationship between the atomic coordination density and the surface strain of two-dimensional heterojunctions. Moreover, the interfacial atomic cohesive energy and the bond energy density varies from case to case. These findings may lead to new materials for related fields. [ABSTRACT FROM AUTHOR]

Two-dimensional transition metal dichalcogenides (TMDs) exhibit an extensive variety of novel electronic properties, such as charge density wave quantum spin Hall phenomena, superconductivity, and Dirac and Weyl semi-metallic properties. The diverse properties of TMDs suggest that structural transformation can be employed to switch between different electronic properties. Intercalation and zero valence doping of molecules and atoms into the van der Waals gap of TMDs have emerged as effective approaches to modify the charge order states of the material. This eventually leads to phase transition or the formation of different phases, thus expanding the electronic, thermoelectric and optical applications of these materials. In this study, electronic and electrochemical energy storage properties of such an intercalated TMD, namely, 2H-TaSe 2 via intercalation of lithium (Li), sodium (Na) and potassium (K) have been investigated. The intercalation of these ions into the dichalcogenide resulted in a modified band structure and novel structural effects, leading to the emergence of a 1 eV band gap. Possibility of electrochemical energy storage application is also explored in this study. Furthermore, the importance of multi orbital electron–electron correlations in intercalated TaSe 2 is also investigated via dynamical-mean-field theory with local density approximation. • DFT+DMFT study of intercalated TaSe 2. • Calculation of DFT optical Properties. • Theoretical angle resolved photoemission spectra map. • Change in the energy range of optical operation due to intercalation. • Ion intercalation capacity and increased electrical conductivity due to intercalation. [ABSTRACT FROM AUTHOR]

• A green bio-based solvent Cyrene was used to separate aromatics from alkanes. • The interaction energy follows sequence 1-methylnaphthalene > indane > decalin > dodecane. • Quantum chemical calculations were used to study the extraction mechanism of Cyrene. • The highest selectivity coefficient for dodecane/1-methylnaphthalene was 106.39. • The interaction force between Cyrene and solute was mainly van der Waals forces. Liquid-liquid extraction is an important technique for separating aromatic and alkane hydrocarbons. The toxicity and pollution problems of traditional solvents are difficult to solve, and the use of green bio-based solvents for diesel fuel dearomatization is of great significance to solve energy and environmental problems. In this paper, Cyrene, a low toxicity, low cost, green composition bio-based solvent, was selected as an extractant to study its ability to remove mono- and bicyclic aromatics from chain alkanes and cycloalkanes, respectively. In addition to the ternary system, the extraction effects under various experimental conditions and multi-component simulated systems were also investigated. The results showed that aromatics and cyclic structures tend to interact more strongly with Cyrene due to differences in solute structure, and therefore polycyclic aromatic hydrocarbons tend to produce larger distribution coefficients. the selectivity coefficients of Cyrene for the four systems were influenced by differences in interaction energies in the order: dodecane/1-methylnaphthalene > dodecane/indene > decahydronaphthalene/1-methylnaphthalene > decahydronaphthalene/indene. At the same time, multi-component simulated oil experiments have demonstrated that Cyrene is equally selective in removing aromatic hydrocarbons from complex components. Quantum chemical calculations were used to investigate the extraction mechanism of Cyrene. The results of Reduced Density Gradient (RDG), Atoms In Molecules (AIM), and Symmetry-Adapted Perturbation Theory (SAPT) energy decomposition proved that the interaction forces between Cyrene and solute molecules are van der Waals forces dominated by dispersion forces and accompanied by some very weak hydrogen bonds. Finally, thermodynamic correlations using the NRTL model were performed to obtain binary interaction parameters for the four systems. The results of this paper indicate that Cyrene, as a new green bio-based solvent, has the potential to be used as an extractant and shows good separation in the removal of long carbon chain aromatic hydrocarbons, and this paper also provides basic data and references for subsequent studies. [ABSTRACT FROM AUTHOR]

• Study of droplet behavior under coupled electric field and initial velocity by molecular dynamics simulation. • Droplets act in three modes at different Weber number ranges: incomplete coalescence, complete coalescence, and non-coalescence. • The fragmentation of droplets at low Weber numbers is associated with ion migration. • Droplets do not coalesce at high Weber numbers owing to the steep angle between the electric field and the centerline of the droplet. • Weak interaction analysis (IGMH) can be used to visualize intermolecular interactions. Herein, the movement of two non-centric droplets in hexane was studied using a molecular dynamics method to understand the microscopic coalescence mechanism of droplets with an initial velocity in an electric field. Unlike previous studies, this study overcame the limitations in experimental conditions and conventional analytical tools to understand the mechanism of droplet coalescence under the coupling effect of electric and velocity fields at the molecular level. This has implications for the development of inkjet printing technology and microfluidics. The analysis of droplet trajectories and centroid distances revealed that the Weber number can be divided into three ranges according to the three modes of droplet behaviour: incomplete coalescence, complete coalescence and non-coalescence. At a low Weber number (We < 1), the inhomogeneous distribution of ions in droplets causes the fragmentation of droplets that are not completely coalesced. The interaction energy and weak interaction analysis shows that hydrogen bonds between water molecules are the strongest, followed by van der Waals interactions, which is very prominent in the first and second coordination layers. Hexane and water molecules exhibit van der Waals interactions. As the Weber number increases from 0 to 5, the total interaction energy between two droplets increases, and the number of hydrogen bonds increases. A decrease in the total interaction energy, number of hydrogen bonds, radial distribution function and coordination number in a single droplet shows that increasing the Weber number loosens the single droplet and simultaneously promotes the coalescence of two droplets. However, when We > 5, the total interaction energy and number of hydrogen bonds between droplets are zero, and the two droplets do not merge. This is because the angle between the electric field and centreline of the droplets is so large that the electric field cannot horizontally act upon the droplets. This study provides a fundamental guide for studying the mechanism of droplet coalescence under the coupling effect of electric and flow fields. [ABSTRACT FROM AUTHOR]

The van der Waals heterostructures, which explore the synergetic properties of 2D materials when assembled into 3D stacks, have already brought to life a number of exciting phenomena and electronic devices. Still, the interaction between the layers in such assembly, possible surface reconstruction, and intrinsic and extrinsic defects are very difficult to characterize by any method, because of the single-atomic nature of the crystals involved. Here we present a convergent beam electron holographic technique which allows imaging of the stacking order in such heterostructures. Based on the interference of electron waves scattered on different crystals in the stack, this approach allows one to reconstruct the relative rotation, stretching, and out-of-plane corrugation of the layers with atomic precision. Being holographic in nature, our approach allows extraction of quantitative information about the 3D structure of the typical defects from a single image covering thousands of square nanometers. Furthermore, qualitative information about the defects in the stack can be extracted from the convergent diffraction patterns even without reconstruction, simply by comparing the patterns in different diffraction spots. We expect that convergent beam electron holography will be widely used to study the properties of van der Waals heterostructures. [ABSTRACT FROM AUTHOR]

Understanding the interactions between biomolecules (proteins) and nanomaterials surface is of great importance for developing new biomedical devices. Diamond-like carbon (DLC) is considered an excellent candidate for coating materials for bone organ and tooth replacement. In this paper, Dispersion-corrected Density Functional Theory (DFT D) calculations were performed to elucidate the adsorption behavior of amino acid molecules over Diamond-Like Carbon (DLC) coatings surfaces. In order to examine the effect of carbon hybridization (sp3/sp2 ratio) on the adsorption process, three kinds of DLC surfaces are selected DLC 1 , DLC 2 , and DLC 3 with sp3/sp2 ratios of 20/80, 52/48, and 76/24 respectively. Molecular optimization, electronic properties, molecular electrostatic potential (MEP), the density of states (DOS), and Infrared analysis for DLC surfaces and amino acids before and after adsorption are investigated. NBO and QTAIM results reveal that the adsorption is physical in nature owing to the presence of non-covalent bonds between the considered molecules. DLC 1 with a low sp3/sp2 ratio has more affinity to amino acids than DLC 2 and DLC 3. [Display omitted] • DFT-D calculations were performed to elucidate the adsorption of amino acids on DLC surfaces. • The adsorption energy values and the partial charges reveal the physical nature of the adsorption. • The energy gap values indicate that there is no charge transfer between the two amino acids and DLCs. • QTAIM results confirm that the interactions between DLCs and amino acids molecules are Van der Waals in nature. • The DLC 1 with sp3/sp2 (20/80) is the best adsorbent of amino acids and is very promising in biomedical applications. [ABSTRACT FROM AUTHOR]

• Overheating in nitramines CACs with DATB &TATB increased thermal sensitivity. • The bonding ‒N‒O···H‒N= in CACs evident by E a vs asym- N-O stretching correlation. • van der Waals forces in CACs evident by E a vs asym- NO 2 stretching correlation. • Heats of combustion as a CACs energy content in linear relation to the ln E a values. The thermolysis of the co-agglomerates (CACs) of the attractive nitramines RDX, BCHMX, HMX and CL-20 with 1,3-diamino-2,4,6-trinitrobenzene (DATB) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) was studied by means of differential thermal analysis (DTA) and differential scanning calorimetry (DSC), using the Kissinger method for output evaluation. The insertion of both DATB and TATB molecules into nitramine crystal lattices markedly increased the thermal sensitivity of the resulting CACs to overheating. Depression in melting points was detected in all CACs and, with the exception of RDX CACs, also in the exothermic peaks. The RDX CACs differ from the other studied CACs by their decomposition in the liquid state. The activation energies (E a) , obtained correlate with asymmetric N-O stretching vibrations, confirming the important influence of ‒N‒O····H‒H= interactions in CACs; a similar correlation with asymmetric NO 2 stretching confirms the interactions of DATB and TATB molecules with nitramine molecules through van der Waals forces. The insertion of DATB or TATB into the crystal lattice of HMX or CL20 changes their polymorphic modification from β- to δ- and in the latter case from ɛ- to β- modifications in the corresponding CACs. The correlations of the E a values with the square of detonation velocity as a representative of performance and with the heat of combustion as a representative of the energy content are consistent with already previously described relationships of this type, including exceptions for pure nitramines. [Display omitted] [ABSTRACT FROM AUTHOR]

The dipole transition moments are given for transitions involving the ground state and excited state C1Π. The TDMs curve of the C1Π-X1Σ+ transition for Zn-RG are analyzed. From their curve changes, it is found that the C1Π state of these molecules have the same properties. [Display omitted] • The ground state and 9 singlet excited states correlate with lowest six dissociation limits of Zn-RG (RG = He, Ne, Ar, Kr, Xe) and the ground state and 2 singlet excited states correlate with lowest two dissociation limits of ZnRn are calculated by CCSD, CCSD(T) and EOM-CCSD methods. • Spectroscopic constants of bound states of Zn-RG (RG = He, Ne, Ar, Kr, Xe, Rn) are evaluated. • The transition dipole moments (TDMs) for Zn-RG molecules are calculated by EOM-CCSD method. • The vibrational band origins, rotational constants and Frank-Condon factors (FCFs) for C1Π-X1Σ+ of Zn-RG are reported. The computations on the potential energy curves (PECs) of the ground state and low-lying singlet excited states for Zn-RG (RG = He, Ne, Ar, Kr, Xe, Rn) molecule have been carried out using coupled-cluster with single and double excitations (CCSD), coupled-cluster with single and double excitations and perturbative contribution of connected triple excitations (CCSD(T)) methods and the equation-of-motion coupled cluster method restricted to single and double excitations (EOM-CCSD). The spectroscopic constants of all the bound states of Zn-RG have been calculated, and comparisons with the available experimental and theoretical works have been made for the ground state and C1Π state of the Zn-RG complexes, reasonable agreement is found. The transition dipole moments (TDMs) functions of C1Π-X1Σ+ and D1Σ+-X1Σ+ transitions, the vibrational band origins, rotational constants and Franck-Condon factors of C1Π-X1Σ+ transition have also been reported, which would be of value to understand the transition properties of Zn-RG. Our study is expected to be helpful for deep understanding on the electronic structure and spectroscopy of Zn-RG van der Waals molecules. [ABSTRACT FROM AUTHOR]

The micro resonant pressure sensor outputs the frequency signals where the distortion does not take place in a long distance transmission. As the dimensions of the sensor decrease, the effects of the van der Waals forces should be considered. Here, a coupled dynamic model of the micro resonant pressure sensor is proposed and its coupled dynamic equation is given in which the van der Waals force is considered. By the equation, the effects of the van der Waals force on the natural frequencies and vibration amplitudes of the micro resonant pressure sensor are investigated. Results show that the natural frequency and the vibrating amplitudes of the micro resonant pressure sensor are affected significantly by van der Waals force for a small clearance between the film and the base plate, a small initial tension stress of the film, and some other conditions. [ABSTRACT FROM AUTHOR]