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The fundamental understanding of the effects of rare earth (RE) on the phase transformation of Fe-based alloys is essential in the development of advanced RE-containing high strength steels. In this work, we investigated the effects of La and Ce on the martensitic phase transformation of Fe in terms of the driving force and minimum energy path (MEP) using the first-principles calculations. The calculations of formation energy show that the RE substitution increases the stabilization of fcc-Fe and decreases that of bcc-Fe, thus decrease the driving force of phase transformation. Meanwhile, the analysis based on the generalized solid-state nudged elastic band (G-SSNEB) method indicates that in the RE-containing systems, an additional energy barrier appears when the phase transformation proceeds along the Bain transition path to c/a ratio of 1.14 in the FM state, which is associated with a sudden decrease in magnetization due to the hybridization between the orbitals of the RE atoms and those of the nearest neighbor Fe atoms. The results of potential-energy surfaces (PES) confirm that magnetic ordering and lattice volume change simultaneously with the Bain transition, and in comparison with pure Fe, the variation between the onset and the end structural volumes of the phase transformation is slight for the RE-containing Fe systems.

Summary Ammonia synthesis is structure sensitive, and a minute change in the catalyst structure would cause a dramatic change in activity. To date, none of the studies reveal the metal size effect at a subnanometer scale on NH3 synthesis, and such investigation remains a challenge. Here, we report the synthesis of Ru catalysts with sizes ranging from single atoms, atomic clusters (ACCs), sub-nanometric clusters, to nanoparticles (NPs) by adjusting precursor and/or loading of Ru. Sub-nanometric Ru catalysts not only exhibit performance different from that of NPs but also follow a different route for N2 activation. The strong intra-cluster interaction of Ru atomic clusters enables the formation of strong interactions of Ru d-orbitals with the σ and π orbitals of N2 molecules, resulting in N2 activation over Ru ACCs to occur more easily than that over Ru NPs. Consequently, Ru ACCs display an unprecedentedly high NH3 synthesis rate and large turnover frequency at mild conditions.

In the current research, the structural parameters of MgxCd1−xX (X = S, Se, Te) ternary semiconductor compounds are determined. Structures of binary compounds are also defined, using the computational approach in zinc blende (B3) structure. For determination of structural parameters, the first principles calculations for energy optimization have been done. As the concentration of Mg dopant goes up, the parameter lattice constant and bulk modulus decreases. The Linear Combination of Atomic Orbital method was used within DFT using CRYSTAL code. The Kohn-Sham Hamiltonian was being constructed using HYBRID B3LYP scheme. The structural parameters are studied in terms of bulk modulus and lattice constant. All the observations, graphs and obtained values are in good coordination with the previously done work.

The structure of 3-Bromo Phenyl Acetic acid (3BPAA) is optimized and its special features are probed by the FTIR, FT-Raman, UV-Visible and NMR with density functional theory calculations by B3LYP level with 6-311++G(d,p) basis set. The electronic properties were discussed with help of UV-Vis spectrum, MEP (Molecular electrostatic potential) and HOMO-LUMO (Highest occupied molecular orbital and Lowest unoccupied molecular orbital) plots. The energy band gap is found as 4.4437eV. The chemical shift is determined from proton and carbon NMR (Nuclear magnetic resonance) plot by Gauge Independent Atomic Orbital (GIAO) method. The surface analysis such as ELF (Electron localization function), LOL (Localized orbital locator) and ESP (Electrostatic potential) maps are plotted by wave function analyzer. Thermodynamic functions are studied and correlated with the graph. FMO and Fukui functions were calculated and found that the title compound is a chemically soft material. The NLO behavior of the compound is also examined and reported to have higher hyperpolarizability value greater than urea, the reference material ensuring good non-linear optical (NLO) activity. The molecular docking is performed by AUTODOCK tool, its study reveals that the title compound binds well with the protein L- glucorante reductose inhibition. Thus the present work study reports the structural, chemical, electronic, thermodynamic and biological activities of 3BPAA.

Zn-Zn bond as one of the metal-to-metal bonds in clusters and molecules is of fundamental interest in many areas of natural science. Neutral boronyl can be viewed as σ radical and has been found in the boronyl metal complexes. However, the complex with Zn-Zn bond stabilized by boronyl ligands has not been found so far. Herein, we report on the computational design of the simplest case of such a system: linear D∞h OBZnZnBO. The structural and electronic properties and chemical bonding on series of zinc complexes Znx(BO)y (x=1,2; y=1,2) with boronyl as ligands have been studied using quantum chemical calculations at the B3LYP and PBE0 level, respectively. For the Zn2(BO)2 cluster, the linear D∞h OBZnZnBO is the global minimum, in which the calculated Zn-Zn bond length of rZn-Zn = 2.400 A at B3LYP level, appears to be close to the latest recommended covalent radii (2.40 A) of the proposed single bond covalent radii of the Zn-Zn. Chemical bonding analyses show that D∞h OBZnZnBO possesses the linear four-center two-electron (4c-2e) σ bond. The σ bond framework has a contribution of Zn orbitals 54%, B orbitals 44%, which involves the Zn 4s 20% and 4p 34%, B 2s 28% and 2p 16%, respectively. Furthermore, the D∞h HZnZnH and NCZnZnCN clusters also exhibit one linear 4c-2e σ bond, due to the secondary contribution from the H s and C sp components, respectively. Linear 4c-2e σ bond greatly stabilizes the dizinc complexes. D∞h OBZnZnBO is thermochemically stable with respect to possible formation channel at room temperature, whereas the exergonic channel, 2ZnBO (C∞v, 2∑g)→OBZnZnBO (D∞h, 1∑g), the formation energy evaluated is -58.75 kcal mol1 at the B3LYP level. Thus D∞h OBZnZnBO as the first observation of Zn-Zn covalent bond in zinc complexes with boronyl as ligands may be synthesized in the laboratory in the near future.

Summary The photomagnetic effect is known to be related only to transition metal atoms with empty orbitals and spin-state changes. In general, noble metals with high electron density cannot be used as photomagnetic materials because of the absence of spin polarization. However, here, we found that photomagnetic-chiral anisotropy (PM-ChA) was generated in chiral nanostructured Au films (CNAFs), and opposite photomagnetic fields (PMFs) were created in the antipodal CNAFs under unpolarized irradiation. The PM-ChA was speculated to arise from directional alignment of opposite spins polarized by the asymmetric spin-orbit coupling due to the opposite effective magnetic fields induced by electron motion in the antipodal helical structure. PM-ChA can be applied in enantiomeric quantification, probably because of the spin polarization coupling between CNAFs and enantiomers. PM-ChA of noble metals generated by directional spin control in helical nanostructures could provide new strategies in quantum technology and theories in magnetophysics.

This work presents a geometry-driven deep learning framework Geometry Orbital of Deep Learning (GOODLE) that accurately predicts all carbon properties in real space and momenta space. We focus on the hybrid carbon orbitals (sp2 and sp3) geometry to establish their deep learning “potential”. We demonstrate its excellent performance with the properties predictions in dual space, including energy, equation of states, phonon structure, electronic band structure, and optical absorption. Capable of obtaining the carbon orbital geometries from small lattice carbon structures, GOODLE can be used for both inorganic carbon allotropes and organic hydrocarbon molecules, including the magic-angle twisted bilayer graphene, with excellent transferability. GOODLE is also available for the nudged-elastic band calculation. Besides, we proposed an analytic geometry condition criterial for the carbon allotropes stability.

On the basis of the higher order perturbation formulas of g-factors for a 4d1 group in tetragonally compressed octahedra, the g-factors, optical absorption, local structure and their concentration dependences of pentavalent molybdenum in 40PbO-(10-x)Y2 O3 -50P2 O5 :xMoO3 (1 ≤ x ≤ 5 mol%) glass are uniformly investigated. The experimental optical absorption spectra and g factors for Mo5+ at various concentrations x are reasonably regenerated by using the reasonable exponential concentration functions of the cubic field parameter Dq, covalent factor N and relative tetragonal compression ratio ρ. The tetragonal compression ratio ρ due to the Jahn-Teller effect was found in the range of 3.8-4.2%. The decreasing trend of Dq and N and the increasing trend of ρ with concentration can be interpreted as the fact that the variations of MoO3 and Y2 O3 concentrations lead to the modulations of local structure and electron cloud distribution around Mo5+ , associated with the adjustment of the glass network. The concentration dependence of optical basicity is also analyzed for the above glass systems.

Superatomic molecular orbitals (SAMOs) have symmetries (angular quantum numbers) similar to those of atoms and thus it is possible to realize Rydberg state excitations (RSEs) in superatomic molecules. In this letter, the feasibility of superatomic Rydberg state excitation (SRSE) is explored using gold superatoms based on first-principles calculations. The results show that the SRSE exists in both the high and low excited states of the gold superatoms and their SAMOs make a major contribution to electronic transitions. The radial distribution function (RDF) of electronic density shows that the main distribution of electrons in the lowest unoccupied molecular orbitals and other unoccupied superatomic molecular orbitals is extremely far from the geometric center and thus they can be unambiguously identified as Rydberg orbitals. We found that due to two-dimensional ductility of planar superatoms’ transition orbitals, superatoms have the superiority in RSE regulation. Our findings provide a new source of superatom-based RSE and will contribute to the regulation and efficient preparation of Rydberg states.

We present a scalable implementation of the $GW$ approximation using Gaussian atomic orbitals to study the valence and core ionization spectroscopies of molecules. The implementation of the standard spectral decomposition approach to the screened Coulomb interaction, as well as a contour deformation method are described. We have implemented both of these approaches using the robust variational fitting approximation to the four-center electron repulsion integrals. We have utilized the MINRES solver with the contour deformation approach to reduce the computational scaling by one order of magnitude. A complex heuristic in the quasiparticle equation solver further allows a speed-up of the computation of core and semi-core ionization energies. Benchmark tests using the GW100 and CORE65 datasets and the carbon 1{\it s} binding energy of the well-studied ethyl trifluoroacetate, or ESCA molecule, were performed to validate the accuracy of our implementation. We also demonstrate and discuss the parallel performance and computational scaling of our implementation using a range of water clusters of increasing size., Comment: 39 pages, 9 figures

In this review, the history and outlook of gas-phase CO2 activation using single electrons, metal atoms, clusters (mainly metal hydride clusters), and molecules are discussed on both of the experimental and theoretical fronts. Although the development of bulk solid-state materials for the activation and conversion of CO2 into value-added products have enjoyed great success in the past several decades, this review focuses only on gas-phase studies, because isolated, well-defined gas-phase systems are ideally suited for high-resolution experiments using state-of-the-art spectrometric and spectroscopic techniques, and for simulations employing modern quantum theoretical methods. The unmatched high complementarity and comparability of experiment and theory in the case of gas-phase investigations bear an enormous potential in providing insights in the reactions of CO2 activation at the atomic level. In all of these examples, the reduction and bending of the inert neutral CO2 molecule is the critical step determined by the frontier orbitals of reaction participants. Based on the results and outlook summarized in this review, we anticipate that studies of gas-phase CO2 activations will be an avenue rich with opportunities for the rational design of novel catalysts based on the knowledge obtained on the atomic level.

As very light fermions, electrons are governed by antisymmetric wave functions that lead to exchange integrals in the evaluation of the energy. Here we use the localized representation of orbitals to decompose the electronic energy in a fashion that isolates the enigmatic exchange contributions and characterizes their distinctive control over electron distributions. The key to this completely general analysis is considering the electrons in groups of three, drawing attention to the curvatures of pair potentials, rather than just their amplitudes and slopes. We show that a positive curvature at short distances is essential for the mutual distancing of electrons and a negative curvature at longer distances is essential to account for the influence of lone pairs on bond torsion. Neither curvature is available in the absence of the exchange contributions. Thus, although exchange energies are much shorter range than Coulomb energies, their influence on molecular geometry is profound and readily understood., The mutual distancing of electrons in molecules is often attributed to electron charge. However, consideration of the curvature of the distance dependence of different contributions to the electronic energy shows that the mutual distancing actually depends on the required antisymmetry of electron wave functions.