Spectroscopy and molecule opacity investigation on excited states of SiS

The SiS molecule,which plays a significant role in space,has attracted a great deal of attention for many years.Due to complex interactions among its low-lying electronic states,precise information regarding the molecular structure of SiS is limited.To obtain accurate information about the structure of its excited states,the high-precision multireference configuration interaction(MRCI)method has been utilized.This method is used to calculate the potential energy curves(PECs)of the 18Λ–S states corresponding to the lowest dissociation limit of SiS.The core–valence correlation effect,Davidson’s correction and the scalar relativistic effect are also included to guarantee the precision of the MRCI calculation.Based on the calculated PECs,the spectroscopic constants of quasi-bound and bound electronic states are calculated and they are in accordance with previous experimental results.The transition dipole moments(TDMs)and dipole moments(DMs)are determined by the MRCI method.In addition,the abrupt variations of the DMs for the 1^(5)Σ^(+)and 2^(5)Σ^(+)states at the avoided crossing point are attributed to the variation of the electronic configuration.The opacity of SiS at a pressure of 100 atms is presented across a series of temperatures.With increasing temperature,the expanding population of excited states blurs the band boundaries.

Mutual neutralization in low-energy collisions of Na^(+)+H^(-)ions

The low-energy mutual neutralization(MN)reactions Na^(+)+H^(-)→Na(nl)+H have been studied by employing the full quantum-mechanical molecular-orbital close-coupling(QMOCC)method over a wide energy range of 10^(-3)-10^(3) e V/u.Total and state-selective cross sections have been investigated and compared with the available theoretical and experimental data,and the state-selective rate coefficients for the temperature range of 100-10000 K have been obtained.In the present work,all the necessary highly excited states are included,and the influences of rotational couplings and 10 active electrons are considered.It is found that in the energy below 10 e V/u,the Na(4s)state is the most dominant exit state with a contribution of approximately 78%to the branch fraction,which is in best agreement with the experimental data.For energies above 10 e V/u,the MN total cross section is larger than those obtained in other theoretical calculations and shows a slow decreasing trend because the main exit states change,when the energy is above 100 e V/u,the dominant exit state becomes the Na(3p)state,while the Na(4s)state becomes the third most important exit state.The datasets presented in this paper,including the potential energy curve,the radial and rotational couplings,the total and state-selective cross sections,are openly available at https://doi.org/10.57760/sciencedb.j00113.00112.

Theoretical study of electron-impact broadening for highly charged Ar XV ion lines

Spectral line widths produced by collisions between charged particles and emitters are of special interest for precise plasma spectroscopy.The highly charged Ar XV ion is demonstrated to have strong intrashell electron interactions,which manifest as an atomic system with many resonance structures,due to the quasi-degeneracy of orbital energies.In this paper we use the relativistic R-matrix method to investigate the electron-impact broadening of highly charged Ar XV ion spectral lines under the impact approximation.It is found that the results considering resonance structures are significantly different from those of the distorted wave approach.Furthermore,we propose a new empirical formula with a correction term to take into account the effect of resonances for electron-impact widths over a relatively wide range of plasma conditions.The corresponding fitting parameters of the new empirical formula for all 47 calculated transitions are also given with an estimated accuracy within 1%,which should be convenient for practical applications.The dataset that supported the findings of this study is available in Science Data Bank,with the link https://doi.org/10.57760/sciencedb.j00113.00101.

From Topological Nodal-Line Semimetals to Quantum Spin Hall Insulators in Tetragonal SnX Monolayers(X=F,Cl,Br,I)

Two-dimensional(2D)topological materials have recently garnered significant interest due to their profound physical properties and promising applications for future quantum nanoelectronics.Achieving various topological states within one type of materials is,however,seldom reported.Based on first-principles calculations and tightbinding models,we investigate topological electronic states in a novel family of 2D halogenated tetragonal stanene(T-SnX,X=F,Cl,Br,I).All the four monolayers are found to be unusual topological nodal-line semimetals(NLSs),protected by a glide mirror symmetry.When spin-orbit coupling(SOC)is turned on,T-SnF and TSnCl are still ascertained as topological NLSs due to the remaining band inversion,primarily composed of Sn pxy orbitals,while T-Sn Br and T-SnI become quantum spin Hall insulators.The phase transition is ascribed to moving up in energy of Sn s orbitals and increasing of SOC strengths.The topology origin in the materials is uniformly rationalized through elementary band representations.The robust and diverse topological states found in the 2D T-SnX monolayers position them as an excellent material platform for development of innovative topological electronics.

Dynamics and Thermodynamics of Porous HMX-like Material Under Shock

Strong shock may induce complex processes in porous materials.We use the newly developed material-point-methodto simulate such processes in an HMX-like material.To pick out relevant information,morphologicalcharacterization is used to treat with the temperature map.Via the Minkowski functional analysis the dynamics andthermodynamics of the shock wave reaction on porous HMX-like material are studied.The geometrical and topologicalproperties of the'hot-spots'are revealed.Numerical results indicate that,shocks in porous materials are not simplejump states as classically viewed,but rather are a complex sequence of compressions and rarefactions.They cover abroad spectrum of states.We can use coarse-grained description to the wave series.A threshold value of temperaturepresents a Turing pattern dynamical procedure.A higher porosity is generally preferred when the energetic materialneeds a higher temperature for initiation.The technique of data analysis can be used to other physical quantities,forexample,density,particle velocity,some specific stress,etc.From a series of studies along the line,one may get a largequantity of information for desiring the fabrication of material and choosing shock strength according to what needed isscattered or connected'hot-spots'.

Interaction of two edge dislocations in free-space propagation

This paper studies in detail the interaction of two edge dislocations nested in a Gaussian beam propagating in free space. It shows that in free-space propagation the edge dislocations are unstable and vanish, and two noncanonical vortices with opposite topological charge take place when off-axis distances cl and c2 of two edge dislocations are nonzero, and the condition k2w08＋ 32c1c2（w02- 2C1C2）Z2 〉 0 is fulfilled （k-wave number, w0-waist width）. A noncanonical vortex appears when one off-axis distance is zero. However, one edge dislocation is stable when two edge dislocations are perpendicular and one off-axis distance is zero. Two perpendicular edge dislocations both with zero off-axis distance are also stable. The analytical results are illustrated by numerical examples.

Simulation Study of Shock Reaction on Porous Material

直接在吃惊下面多孔的材料当模特儿是一个复杂问题。我们经由最新发达的材料点方法调查如此的一个系统。吃惊力量和孔尺寸的效果是主要担心。为一样的孔， mean-void-size 的效果被检查。混合的本地骚乱和体积驱散是二重要机制让动能的转变加热，这被发现。当孔是很小的时，震惊的部分可以到达一个动态稳定的状态；在下游的部分的虚空反映背 rarefactive 波浪并且导致吝啬的密度和压力的细微摆动；为孔的一样的价值，更大的 mean-void-size 做更高吝啬的温度。当孔变得大时，水动力学数量在整个装载吃惊的过程期间与时间变化：在起始的阶段以后，吝啬的密度和压力减少，而是温度与更高的率增加。本地密度，压力，温度和粒子速度的分布通常是 non-Gaussian 并且与时间变化。变化的率取决于孔价值， mean-void-size 和吃惊力量。越强壮装载吃惊，孔完成越多 stronger。这个工作为快过程提供补充给实验并且在精力和动量交通揭示更基本的机制。

Review of quantum collision dynamics in Debye plasmas

Hot,dense plasmas exhibit screened Coulomb interactions,resulting from the collective effects of correlated many-particle interactions.In the lowest particle correlation order(pair-wise correlations),the interaction between charged plasma particles reduces to the DebyeeHu¨ckel(Yukawa-type)potential,characterized by the Debye screening length.Due to the importance of Coulomb interaction screening in dense laboratory and astrophysical plasmas,hundreds of theoretical investigations have been carried out in the past few decades on the plasma screening effects on the electronic structure of atoms and their collision processes employing the DebyeeHu¨ckel screening model.The present article aims at providing a comprehensive review of the recent studies in atomic physics in Debye plasmas.Specifically,the work on atomic electronic structure,photon excitation and ionization,electron/positron impact excitation and ionization,and excitation,ionization and charge transfer of ion-atom/ion collisions will be reviewed.

Density-functional theory study of the effect of pressure on the elastic properties of CaB_6

Under high pressure, the long believed single-phase material CaB6 was latterly discovered to have a new phase tI56. Based on the density-functional theory, the pressure effects on the structural and elastic properties of CaB6 are obtained. The calculated bulk, shear, and Young’s moduli of the recently synthesized high pressure phase tI56-CaB6 are larger than those of the low pressure phase. Moreover, the high pressure phase of CaB6 has ductile behaviors, and its ductility increases with the increase of pressure. On the contrary, the calculated results indicate that the low pressure phase of CaB6 is brittle. The calculated Debye temperature indicates that the thermal conductivity of CaB6 is not very good. Furthermore, based on the Christoffel equation, the slowness surface of the acoustic waves is obtained.

Positron-Impact Excitation of Hydrogen Atoms in Debye Plasmas

在血浆环境嵌入的氢原子的正电子影响刺激用靠近联合的近似被调查从对没有包括任何电子偶素形成隧道，和刺激十字的中间的精力区域低为 1s 的节- 2s ， 1s - 2p 和 2s - 2p 过程在一个宽 Debye 参数范围被计算。屏蔽相互作用，由 Debye-Huckel 模型，描述了减少联合矩阵元素，从一些导致刺激十字节的减小百分比到十的一大小。这将显著地在紧张和位置改变氢的光谱学，它应该在一些特定的血浆条件下面在模拟和诊断被考虑。[从作者抽象]

Evolution of emergent C-points,L-lines,and C-lines in free space

Polarization singularities,which emerge from the incoherent superposition of two vector electric fields with the same frequency,and their evolution in free space are studied analytically and illustrated by numerical examples.It is shown that there exist C-points,L-lines,in particular,C-lines in incoherently superimposed two-dimensional wavefields.Usually,the C-lines are unstable and disappear during the free-space propagation.The motion,pair creation-annihilation process of the emergent C-points,as well as the distortion of the L-lines may take place,and the degree of polarization of the emergent C-points varies upon propagation and may be less than 1.

Construction of surface lattice oxygen in metallic N-CuCoS1.97 porous nanowire for wearable Zn-air battery

Achieving high activity and stability oxygen evolution reaction(OER) catalysts to optimize the efficiency of metal-air battery, water splitting and other energy conversion devices, remains a formidable challenge.Herein, we demonstrate the metallic porous nanowires arrays with abundant defects via nitrogen and copper codoped CoS1.97 nanowires(N-CuCoS1.97 NWs). The N-CuCoS1.97 NWs can serve as an excellent OER self-supported electrode with an overpotential of 280 mV(j = 10 m A cm-2) and remarkable long-term stability. The X-ray absorption near-edge structure(XANES) and X-ray photoelectron spectrum(XPS) measurements confirmed the surface lattice oxygen created on the N-CuCoS1.97 NWs during OER. Then, the density function theory(DFT) results evident that lattice oxygen constructed surface of N-CuCoS1.97 NWs has more favorable OER energetic profiles and absorption for reaction intermediate. More importantly,the flexible and wearable Zn-air battery fabricated by the N-CuCoS1.97 NWs shows excellent rechargeable and mechanical stability, which can be used in portable mobile device.

Experimental Study on Penetration and Perforation of Laminated Kevlar

The penetration behavior and perforation characteristics of Kevlar/Epoxy laminates with various thickness in quasi-static and ballistic perforation penetrated by steel projectiles with different noses are investigated. Quasi-static tests are conducted on MTS810 testing system. The results indicate that global deformation is the major mechanism of energy absorption and woven laminates exhibit larger energy dissipation than that of angle-plied laminates. Therefore, the woven laminates have better quasi-static penetration resistance. Ballistic tests with velocity of 200-700 m/s are executed by using a powder gun with 7.62 mm barrel. Comparing ballistic experimental results with those under quasi-static condition, both the perforation performance and the failure modes are related closely to the speed of penetrator. Quite different from quasi-static tests, ballistic tests indicate that thick angle-plied laminate targets are even better than woven laminates in resisting ballistic impact. It is observed that the damage zone of the laminate is localized highly with the increasing of the impact velocity and correspondingly, the failure modes are more manifold. The shape of projectile noses affects the impact resistance of laminated Kevlar significantly in the range of velocity around the ballistic limit..

Nonradiative charge transfer in collisions of protons with rubidium atoms

The nonradiative charge-transfer cross sections for protons colliding with Rb（5s） atoms are calculated by using the quantum-mechanical molecularorbital close-coupling method in an energy range of 10-a keV-10 keV. The total and state-selective charge-transfer cross sections are in good agreement with the experimental data in the relatively low energy region. The importance of rotational coupling for chargetransfer process is stressed. Compared with the radiative charge-transfer process, nonradiative charge transfer is a dominant mechanism at energies above 15 eV. The resonance structures of state-selective charge-transfer cross sections arising from the competition among channels are analysed in detail. The radiative and nonradiative1 charge-transfer rate coefficients from low to high temperature are presented.

Phase transition and thermodynamic properties of BiFeO_3 from first-principles calculations

The first-principles projector-augmented wave method employing the quasi-harmonic Debye model,is applied to investigate the thermodynamic properties and the phase transition between the trigonal R3c structure and the orthorhombic Pnma structure.It is found that at ambient temperature,the phase transition from the trigonal R3c phase to the orthorhombic Pnma phase is a first-order antiferromagnetic-nonmagnetic and insulator-metal transition,and occurs at 10.56 GPa,which is in good agreement with experimental data.With increasing temperature,the transition pressure decreases almost linearly.Moreover,the thermodynamic properties including Grneisen parameter,heat capacity,entropy,and the dependences of thermal expansion coefficient on temperature and pressure are also obtained.

Lévy Stable Distribution and [0, 2] Power Law Dependence of Acoustic Absorption on Frequency in Various Lossy Media

Absorption of acoustic wave propagation in a large variety of lossy media is characterized by an empirical power law function of frequency, α0｜ω＋^Ⅳ. It has long been noted that the exponent y ranges from 0 to 2 for diverse media. Recently, the present author J. Acoust. Soc. Am. 115 （2004） 1424] developed a fractional Laplacian wave equation to accurately model the power law diss^aation, which can be further reduced to the fractional Laplacian diffusion equation. The latter is known underlying the Lévy stable distribution theory. Consequently, the parameters y is found to be the Lévy stability index, which is known to be bounded within 0 〈 y ≤2. This finding first provides a theoretical explanation of empirical observations y ∈ [0, 2]. Statistically, the frequencydependent absorption can thus be understood a Lévy stable process, where the parameter y describes the fractal nature of attenuative media.

Potential Energy Surfaces of Nitrogen Dioxide for the Ground State

The potential energy function of nitrogen dioxide with the C2v symmetry in the ground state is represented using the simplified Sorbie-Murrell many-body expansion function in terms of the symmetry of NO2. Using the potential energy function, some potential energy surfaces of NO2（C2v, X^-^2A1）, such as the bond stretching contour plot for a fixed equilibrium geometry angle θ and contour for O moving around N-O （R1）, in which R1 is fixed at the equilibrium bond length, are depicted. The potential energy surfaces are analysed. Moreover, the equilibrium parameters for NO2 with the C2v, Cs and Dsn symmetries, such as equilibrium geometry structures and energies, are calculated by the ab initio （CBS-Q） method.

Variation of Ionization Mechanisms with q in the Collision of He^2＋ with C^q＋

The ionization process in the collisions of He^2＋ with C^q＋ （q = 0-5） is investigated by using the continuum-distorted-wave eikonal-initial-state approximation. Double-differential cross sections for 1s and 2s sub-shells are obtained at the electron-ejected angle θ = 0° with the projectile energy ranging from 30keV/u to 10MeV/u. Variation of ionization mechanisms with q in C^q＋ is studied, and the dependences on the projectile energies and target sub-shells are also discussed. It is found that in the whole energy range, the absolute values of soft collision （SC） and binary encounter （BE） peaks decrease with increasing q. For the lower incident energies, the electron capture to the projectile continuum （ECC） peak decrease with increasing q as well as SC and BE peaks. For the higher incident energies （〉 1 MeV/u）, the absolute value of ECC peak increases with increasing q, so that the crossings of cross sections appear for C^q＋ with different q. This can be explained by the matching of velocities between the projectile and the electron initially bound to the target.

Disentangling the Effects of Thickness of the Neutron Skin and Symmetry Potential in Nucleon Induced Reactions on Sn Isotopes

对称精力的密度依赖和在质子(中子) 的中子皮肤的厚度的效果在 Sn 同位素上导致了反应借助于改进分子的动力学模型被调查。调查证明为质子的反应十字节的目标尺寸依赖在 Sn 同位素上导致了反应对对称精力和对目标的中子皮肤的厚度敏感的更少的密度依赖敏感原子核，而是那，因为中子在 Sn 同位素上导致了反应，它是对对称精力的密度依赖敏感、对目标原子核的中子皮肤的厚度敏感的更少。

Nonparaxial propagation of phase-flipped Gaussian beams

This paper derives the closed-form expressions for nonparaxial phase flipped Gaussian （PFG） beams propagating in free space, through a knife edge and an aperture, which enable us to study nonparaxial propagation properties of PFG beams and to compare nonparaxial results with paraxial ones. It is found that the f parameter, offsetting distance of the knife edge and truncation parameter affect the nonparaxial beam propagation properties. Only under certain conditions the paraxial approximation is applicable. The results are illustrated by numerical examples.