C4F7N with excellent insulation performance has been proposed to replace the traditional SF6 as a new insulating medium in power equipment. In the present study, the molecular structure and radiative efficiency (RE) of C4F7N are calculated and compared with SF6 based on DFT calculation. The decomposition of pure C4F7N and the basic interactions between C4F7N and hydroxyl radical in the constructed co-crystal of C4F7N-H2O have been simulated by applying Monte-Carlo calculation and Car-Parrinello molecular dynamics (CPMD) method, in order to obtain reasonable and full-scale atmospheric dissociation processes. Then the detailed decomposition pathways are learned with DFT method of M062X. The rate constants of different pathways are further applied for calculating the atmosphere lifetime of C4F7N, to evaluate the possibility of applying it as an alternative gas of SF6 in power equipment. All the atmospheric chemical behaviours are determined by electronic structure and reflected by the decomposition pathways of C4F7N with interacting with hydroxyl radicals. Rather than traditional hypothesizing reaction models, this study provides a reasonable and practicable method to evaluate more alternative protective gas for understand the greenhouse effect.

In this work, we propose a technique for the use of fermionic neural networks (FermiNets) with the Slater exponential Ansatz for electron-nuclear and electron-electron distances, which provides faster convergence of target ground-state energies due to a better description of the interparticle interaction in the vicinities of the coalescence points. Our analysis of learning curves indicates on the possibility to obtain accurate energies with smaller batch sizes using arguments of the bagging approach. In order to obtain even more accurate results for the ground-state energies, we propose an extrapolation scheme for estimating Monte Carlo integrals in the limit of an infinite number of points. Numerical tests for a set of molecules demonstrate a good agreement with the results of the original FermiNets approach (achieved with larger batch sizes than required by our approach) and with results of the coupled-cluster singles and doubles with perturbative triples (CCSD(T)) method that are calculated in the complete basis set (CBS) limit.

Experimental and theoretical studies show that two-dimensional (2D) materials have great potential applications in the fields of optoelectronics, semiconductors and spintronic devices. Based on the First Principles, the stability, band structure, electronic properties and optical properties of hydrogenated C3B, a new graphene like two-dimensional (2D) material, are studied in this paper. The results show that: firstly, with the increase of hydrogenation degree, the sp2 orbital hybridization in C3B structure gradually transits to a more stable sp3 mode, and the valence band energy near the Fermi level decreases; Secondly, adsorbed H atoms can regulate the bandgap of C3B. When the number of adsorbed H is even, C3B structure behaves as a semiconductor, and meanwhile the bandgap increases. When H atoms is odd, C3B is easy to show metallicity; Finally, the main absorption peak of the optical absorption spectrum decreases first and then increases with the increase of H concentration. The law of the secondary absorption peak is opposite to the main peak. When the ratio of hydrogenation is 50%, an obvious secondary absorption peak appears. This study confirms that hydrogenation is an effective way to regulate the electronic properties of materials, which can expand the application of 2D material C3B in optoelectronic devices.

A proper benchmarking on the properties of HF and its dimer inside C60 using density functional theory (DFT) based approaches is presented. For this purpose, 10 different DFT functionals following Jacob’s Ladder have been chosen. Geometrical parameters, viz., bond length, bond angle, etc., and dipole moment have been computed. Two types of orientations, viz., L-shaped and anti-parallel of (HF)2 inside C60 are considered, the latter with an extremely short hydrogen bond. HF bond lengths are elongated upon encapsulation in comparison to its free state analogue. The calculated stability of HF@C60 is functional dependent whereas, (HF)2C60 is thermodynamically unstable for all the functionals. The kinetic stability of (HF)2@C60 is observed through ADMP simulation at 300K temperature. The red shift in HF stretching frequencies is noticed in all cases. NCI analysis exhibits a non-covalent type interaction between HF dimer and the C60 cage. The total interaction energy is found to be negative for HF@C60. EDA analysis showed a high value of repulsive ΔEpauli which makes the (HF)2@C60 system unstable except for the functional BP86-D3 of GGA family. Furthermore, QTAIM analysis is performed and confirmed the presence of (3, -1) bond critical point along the hydrogen bond region for L-shaped (HF)2C60.

In this account we report an implementation of the quantum trajectory-guided adaptive Gaussian (QTAG) method in a modular open-source Libra package for quantum dynamics calculations. The QTAG method is based on a representation of wavefunctions in terms of a quantum trajectory-guided adaptable Gaussians basis and is generalized for time-propagation on multiple coupled surfaces to be applicable to model nonadiabatic dynamics. The potential matrix elements are evaluated within either the local harmonic or bra-ket-average (linear) approximations to the potential energy surfaces, the latter being a more practical option. Performance of the QTAG method is demonstrated and discussed for the Holstein and Tully models, which are the standard benchmarks for method development in the area of nonadiabatic dynamics.

Density functional theory (DFT) was used to calculate the most stable structures of Gen (n=2-5) clusters as well as the adsorption energies of Gen (n=2-5) clusters after adsorbing single water molecule. The calculation of the reaction paths between Gen (n=2-5) and single water molecule shows that water molecule can react with Gen (n=2-5) clusters to dissociate to produce hydrogen, and O atoms mix with the clusters to generate GenO (n=2-5). According to the energy change of the reactions, the Ge2 cluster is the most efficient among Gen (n=2-5) clusters reacting with single water molecule. The NPA and DOS respectively proved that the Ge atoms in the product don’t reach the highest valence, and it was jointly predicted that GenO (n=2-5) might continue to react with more water molecules. Our findings contribute to better knowledge of Ge’s chemical reactivity, which could aid in the development of effective Ge-based catalysts and hydrogen-production methods.

In this study, the improved Tietz potential was used to describe the internal vibration of a diatomic molecule. With the help of the expression for bound state energy levels, a more generalized equation for the upper bound vibrational quantum number and canonical partition function were obtained for the diatomic system. The obtained partition function was used to derive analytical equation for the prediction of constant pressure (isobaric) molar heat capacity of diatomic molecules. The analytical model was used to predict the constant pressure molar heat capacity data of the ground state CO, BBr, HBr, HI, P2, KBr, Br2, PBr, SiO and Cl2 molecules. The upper bound vibrational quantum number obtained for the molecules are 85, 100, 21, 21, 115, 301, 89, 157, 110 and 67. The computed average absolute deviation are 2.3462%, 1.1342%, 2.3350%, 1.9078%, 0.7268%, 2.4041%, 1.7849%, 1.8989%, 2.5209% and 2.1523%. The present results are in good agreement with available literature data on gaseous molecules.

Understanding the surface chemistry of nanostructured TiO2 has long been a priority to improve photochemical device efficiency. Faceted nanoparticles, characterized by known facets not at thermodynamically ideal ratios, are particularly challenging to model due to the large number of chemical and computational parameters that must be chosen for which there is no experimental guidance. This research supplies a modeling framework for faceted TiO2 nanoparticles that provides rationale for such decisions. By performing full DFT optimization and characterization on a series of inter-related anatase TiO2 nanoparticles displaying {101}, (001), and {010} facets with sizes up to 202 TiO2 units, parameter space is mapped with regard to particle size, shape, defects, and optimization protocol. Specifically, it is shown that pre-optimization is necessary in order to achieve a sufficiently delocalized electronic structure, and the increased reorganization afforded by removing higher coordinated Ti atoms compensates the high formation energy of creating these defects. Furthermore, by characterizing differently shaped nanoparticles with the same number of TiO2 units, this research provides direct observation of shape effects on nanoparticles.

A quinoline derivative, 4-(quinolin-2-ylmethylene)aminophenol was synthesized and structurally characterized by single crystal X-ray diffraction. The crystal packing behaviour and intermolecular interactions were examined by Hirshfeld surface analyses, 2D fingerprint plots and QTAIM analysis. The second order nonlinear response of 4-(quinolin-2-ylmethylene)aminophenol molecule immersed in DMSO was investigated at PCM/DFT/CAM-B3LYP/6-311++G(d,p) level. Theoretical calculations of the Hyper-Rayleigh scattering first hyperpolarizability were performed using two different procedures, the Sum-over-states scheme and the energy derivative method from Gaussian16. The HRS first hyperpolarizability results were compared with obtained for other organic compounds and shown that the 4-(quinolin-2-ylmethylene)aminophenol presents a good nonlinear optical response.

In order to quantify the site-dependent correlation strengths in terms of the quasi-particle weights and the occupation numbers of 5f electrons in alpha phase plutonium metal with eight crystallographically nonequivalent atomic sites Pun (n=1~8), we perform a first principles calculation by using a many-body method merging density functional theory (DFT) with dynamical mean-field theory (DMFT) plus the relativistic and correlation effects. The quasi-particle weight, the electronic spectrum function, the hybridization function, as well as the occupation number of Pu 5f electrons all suggest that Pu1 and Pu8 atoms have the most itinerant and the most localized 5f electrons, respectively, while the other atoms Pun (n=2~7) exhibit an intermediate correlation strength. The quasi-particle weights demonstrate that only the jj or intermediate coupling scheme is more appropriate for Pu 5f electrons in comparison with the Russel-Saunders (LS) scheme. The electronic spectrum function and the occupation analysis establish that Pu 5f electrons simultaneously have dual itinerant and localized regimes with average 5f occupation numbers of nf between 4.8994 and 4.9628, which are mainly composed of 5f4, 5f5 and 5f6 configurations, irrespective of different atomic sites. Finally, we also estimate the so-called quasi-particle band structure to directly compare with an experimental angle-resolved photoemission spectrum (ARPES).

Nitric oxide (NO) is a ubiquitous signaling molecule in a variety of physiological and pathological process in living organisms. A two-photon probe, i.e., 2-acetyl-6-dialkylaminonaphthalene as the reporter and an o-diaminobenzene as the reaction site for NO, linked by prolinamide (ANO1), has been synthesized. Based on the experimental study, five other two-photon probes have been designed by substituting the naphthalene fluorophore in ANO1 with the luciferin analogue (ANO2), pyrene (substitution at 1,6-position, ANO3, and 2,7-position, ANO3’), fluorene (ANO4), and boron-dipyrromethene (ANO5) units. DFT/TDDFT studies have been conducted on both experimental two-photon probe ANO1 and designed ANOn (n=2–5). Our results indicated that for designed probes, both absorption and emission spectra show red shifts compared with ANO1. The one- and two-photon absorption band positions as well as the emission wavelength do have no significant change for each probe before and after reaction with NO. However, the fluorescence intensities are enhanced after reaction with NO. ANO3 and ANO4 have large two-photon absorption cross sections. Furthermore, analysis of molecular orbitals is exhibited to interpret the photoinduced electron transfer mechanism between the donor and acceptor.

I would like to submit an erratum for the article with the title ‘Development of Kinetic Energy Density Functional Using Response Function Defined on the Energy Coordinate’ (Int. J. Quantum Chem. 2022;e26969, https://doi.org/10.1002/qua.26969). The corresponding author of the article is Hideaki Takahashi. The author found an error in producing the graph with the legend ‘OF-DFT’ in Fig. 8 in the article. The error in the graph is attributed to the fact that the atomic response function was spuriously multiplied by 2. We refer the editor to the main text of the erratum in more details. The graph was revised using the amended source code. Fortunately, it was found that the corrected graph was changed favorably as compared to the original one, showing better agreement with the reference calculation.

A set of new rasagiline derivatives is presented. They were designed to be antioxidant compounds with the potential to be used for treating neurodegenerative disorders. They are expected to be multifunctional molecules that can help reduce oxidative stress, which is thought to contribute to neurodegenerative disorders. The CADMA-Chem computational protocol was used to produce rasagiline derivatives and to evaluate their likeliness as oral drugs and antioxidants. Three of them were identified as the most promising ones. They are proposed to be better free radical scavengers than rasagiline. In addition, they are expected to keep the parent's molecule neuroprotective capability. Hopefully, the results presented here would promote further experimental and theoretical investigations on these compounds.

Magnesium-based hydrogen storage material (MgH2) has attracted much attention due to its high hydrogen storage density (7.6 wt%). However, the high hydrogen dissociation enthalpy and slow hydrogen dissociation rate in bulk Mg hinder its wide application in the efficient hydrogen storage. In the present work, we study the hydrogen adsorption and desorption reactions of MgmHn (m = 1-6) nanoclusters using density functional theory (DFT). From the global search for the configurations of MgmHn nanoclusters, we found not only stable saturated MgmHn (n = 2m) nanoclusters, but four hydrogen-enriched MgmHn (n:m>2:1) nanoclusters, Mg3H7, Mg4H9, Mg5H11, Mg6H13, with the hydrogen storage density higher than 8.3 wt%. The electronic-structure calculations indicate that the stability of the hydrogen-enriched cluster gets relatively higher for larger nanocluster. The ab initio dynamics simulations shows that all hydrogen-enriched clusters have very fast hydrogen dissociation rates, which is promising for the hydrogen dissociation at ambient temperature and pressure. This work provides insights into the hydrogen storage mechanism of nano-magnesium materials.

Ab initio calculations were carried out to understand the effect of electron donating groups (EDG) and electron withdrawing groups (EWG) at the C5 position of cytosine (Cyt) and saturated cytosine (H2Cyt) of the deamination reaction. Geometries of the reactants, transition states, intermediates, and products were fully optimized at the B3LYP/6-31G(d,p) level in the gas phase as this level of theory has been found to agree very well with G3 theories. Activation energies, enthalpies, and Gibbs energies of activation along with the thermodynamic properties (ΔE, ΔH, and ΔG) of each reaction were calculated. A plot of the Gibbs energies of activation (ΔG‡) for C5 substituted Cyt and H2Cyt against the Hammett σ-constants reveal a good linear relationship. In general, both EDG and EWG substituents at the C5 position in Cyt results in higher ΔG‡ and lower σ values compared to those of H2Cyt deamination reactions. C5 alkyl substituents (−H, −CH3, −CH2CH3, −CH2CH2CH3) increase ΔG‡ values for Cyt, while the same substituents decrease ΔG‡ values for H2Cyt which is likely due to steric effects. However, the Hammett σ-constants were found to decrease for both the Cyt and H2Cyt. Both ΔG‡ and σ values decrease for the substituents Cl and Br in the reaction Cyt, while ΔG‡ values increase and σ decrease in the reaction H2Cyt. This may be due to high polarizability of bromine which results in a greater stabilization of the transition state in the case of bromine compared to chlorine. Regardless of the substituent at C5, the positive charge on C4 is greater in the TS compared to the reactant complex for both the Cyt and H2Cyt. Moreover, as the charges on C4 in the TS increase compared to reactant, ΔG‡ also increase for the C5 alkyl substituents (-H, −CH3, −CH2CH3, −CH2CH2CH3) in Cyt, while ΔG‡ decrease in H2Cyt. In addition, analysis of the frontier MO energies for the transition state structures shows that there is a correlation between the energy of the HOMO‒LUMO gap and activation energies.

Hydrogen is regarded as one of the most potential sustainable energy sources in the future. applications including transportation. Still, the event of materials for its storage is difficult notably as a fuel in vehicular transport. Nanocones are a promising hydrogen storage material. Silicon, germanium, and tin carbide nanocones have recently been proposed as promising hydrogen storage materials. In the present study, we have investigated the hydrogen storage capacity of iC,GeC and SnC nanocones functionalized with Ni. The functionalized Ni a are found to be adsorbed on iCNC,GeCNC and SnCNC with an adsorption energy of -5.56, -6.70 and -4.25 eV. The functionalized iCNC,GeCNC and SnCNC bind up to seven, six and four molecules of hydrogen with the adsorption energy of (-0.34, -0.35 and -0.26 eV) and an average desorption temperature of around 434, 447 and 332K (ideal for fuel cell applications). The SiC, GeC, and SnC nanocones systems exhibit a maximum gravimetric storage capacity of 12.51, 7.78 and 4.08 wt%. We suggested that Ni- SiCNC and Ni- GeCNC systems can act as potential H2 storage device materials because of their higher H2 uptake capacity as well as there with strong interaction adsorbed hydrogen molecules than Ni- SnCNC systems. The hydrogen storage reactions are characterized in terms of the charge transfer, the partial density of states (PDOS), frontier orbital band gaps, isosurface plots, and electrophilicity are calculated for the functionalized and hydrogenated SiC,GeC and SnC nanocones.

Here we show that substituting the ten protons in the dianion of a bispentalene derivative (C18H102-) by six Si2+ dications produces a minimum energy structure with two planar tetracoordinate carbons (ptC). In Si6C18, the ptCs are embedded in the terminal C5 pentagonal rings and participate in a three-center, two-electron (3c-2e) Si-ptC-Si σ-bond. Our exploration of the potential energy surface identifies a triphenylene derivative as the putative global minimum. But robustness to Born-Oppenheimer molecular dynamics (BOMD) simulations at 900 and 1500 K supports bispentalene derivative kinetic stability. Chemical bonding analysis reveals ten delocalized π-bonds, which, according to Hückel’s 4n+2 π-electron rule, would classify it as an aromatic system. Magnetically induced current density analysis reveals the presence of intense local paratropic currents and a weakly global diatropic current, the latter agreeing with the possible global aromatic character of this specie.

The oxygen electroreduction mechanism on the V- and Nb-doped nitrogen-codoped (6,6)armchair carbon nanotube with incorporated MN4 fragment has been studied using the ωB97XD and PBE density functional theory approaches. The metal center in MN4 fragment and the adjacent NC=CN double bond (C2 site) of the support have been revealed as active centers. The metal active centers turned out to be irreversibly oxidized at the first step of ORR affording stable O*, 2O*, or O*HO* adsorbates depending on the applied electrode potential U, that makes them no longer active in ORR. Therefore, the C2 site comes at the forefront in ORR catalysis. Among the metal oxidized forms M(O)N4–, M(O)(O)N4– and M(O)(OH)N4–CNT, the C2 site of the latter turned out to be most active for 4e dissociative ORR. For both metals the last protonation/electron transfer step, HO* + H* = H2O, is the rate-limiting step. The alternative hydrogen peroxide formation is not only thermodynamically less favorable but also kinetically slower than the 4e dissociative ORR route on the C2 site of model M(O)(OH)N4–CNT catalyst.