46.8MeV的 ~(12)C非弹性散射

在Glauber多重散射理论框架下,使用跃迁密度方法和三种N-N湮没势,计算了46·8MeV的反质子在~(12)C上的非弹性散射微分截面.理论曲线与实验数据符合得较好.     

Ab initio MRCI＋Q study on potential energy curves and spectroscopic parameters of low-lying electronic states of CS＋

Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states have not been well investigated. In this paper, the electronic states of CS＋ are studied by employing the internally contracted multireference configuration interaction method, and taking into account relativistic effects （scalar plus spin–orbit coupling）. The spin–orbit coupling effects are considered via the state-interacting method with the full Breit–Pauli Hamiltonian. The potential energy curves of 18 Λ–S states correlated with the two lowest dissociation limits of CS＋ molecular ion are calculated, and those of 10 lowest Ω states generated from the 6 lowest Λ–S states are also worked out. The spectroscopic constants of the bound states are evaluated, and they are in good agreement with available experimental results and theoretical values. With the aid of analysis of Λ–S composition of Ω states at different bond lengths, the avoided crossing phenomena in the electronic states of CS＋ are illuminated. Finally, the single ionization spectra of CS （X1Σ＋） populating the CS＋（X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋） states are simulated. The vertical ionization potentials for X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋ states are calculated to be 11.257, 12.787, 12.827, and 15.860 eV, respectively, which are accurate compared with previous experimental results, within an error margin of 0.08 eV~0.2 eV.     

Relativistic treatment of the spin-zero particles subject to the second Poschl-Teller-like potential

The three-dimensional Klein-Gordon equation is solved for the case of equal vector and scalar second Poschl-Teller potential by proper approximation of the centrifugal term within the framework of the asymptotic iteration method. Energy eigenvalues and the corresponding wave function are obtained analytically. Eigenvalues are computed numerically for some values of n and It is found that the results are in good agreement with the findings of other methods for short-range potential.     

CL20-TNT共晶高温热解的ReaxFF/lg反应力场分子动力学模拟

ReaxFF/lg势函数是在ReaxFF的基础上增加了对范德华引力的描述, 因此可以更好地用于描述晶体密度和结构, 而含能材料密度很大程度上影响着爆轰的宏观性质(如爆速、反应区宽度、能量输出结构等). 本文采用ReaxFF/lg反应力场分析了高温条件下凝聚相CL20-TNT共晶的初始分解情况, 并通过简单的指数函数拟合势能演化曲线获得了平衡和诱导期以及整体反应时间, 随后通过反应速率方程得到了共晶热解的活化能E_a (185.052 kJ/mol). CL20-TNT共晶热解过程中CL20分子均在TNT之前分解完毕, 并且随着温度的升高, TNT的分解速率明显加快, 温度越高二者完全分解所需的时间越接近. 有限时间步长下的产物识别分析显示主要产物为NO₂, NO, CO₂, N₂, H₂O, HON, HNO₃. NO₂是C–NO₂和N–NO₂键均裂共同贡献的结果, 其产量快速地增加, 达到峰值后开始减少, 此过程伴随着NO₂参与其他反应使得NO₂中的N原子进入到其他的含N 分子中. 次要产物主要为CO, N₂O, N₂O₅, CHO. N₂O具有很强的氧化能力, 使其分布有着剧烈的波动特征. 关键词： 共晶结构 高温热解 ReaxFF/lg 势函数 分子动力学     

He原子与O2分子相互作用势及碰撞微分截面的研究

本文用量子力学从头算方法深入研究了He原子与O2分子的相互作用势,选定CCSD(T)/6-311++G(3df,2pd)方法和基组,同时采用了Boys和Bernardi提出的Full Couterpoise方法消除了计算中的基组重叠误差(BSSE),得出了该体系的各向异性相互作用势的单点能数据,通过拟合得到了较为准确的He-O2体系相互作用势的解析表达式.采用精确度较高的密耦(Close-Coupling)近似方法,计算了He-O2碰撞体系的碰撞激发微分截面,计算得到的微分截面数据与实验值符合较好,并得出了不同碰撞能量时He原子与O2分子的碰撞的微分截面的规律.     

基于MATLAB的静电场模拟

在静电场中引入电位和电场强度后,通过等电位线图和场强分布图可以具体的描述静电场这种抽象的物质场。传统的静电场模拟实验直观地展现出了静电场的分布从而形象地描述了静电场,由于这种方法属于类比模拟,所以存在一定的缺陷(比如不直接,不能描述立体规律等等)。随着计算机技术的发展,利用计算机技术来模拟静电场等物质场逐渐成为趋势。通过借鉴大量资料简要地介绍了如何利用计算机模拟静电场,如何利用MATLAB软件模拟静电场的问题。     

互感系数M12=M21的证明

从定义、磁能、磁矢势、磁偶极子、自由能5个方面出发分别证明了互感系数M12=M21,并对几种证明方法进行了分析对比,提出了自己的看法.     

SF分子基态及低激发态势能函数与光谱常数的研究

采用含Davidson修正的内收缩多参考组态相互作用的方法和考虑相对论修正, 在价态范围内的最大相关一致基 aug-cc-pV6Z 的条件下, 对SF分子的基态²∏及几个低激发态⁴∑^-, ²∑^-, ²Δ进行了势能扫描计算. 对SF分子的势能曲线进行拟合, 得到了该分子的光谱常数R_e, ω_e, ω_eχ_e, D₀, D_e, B_e和 α_e, 通过比较发现它们与已有的实验结果较为一致. 利用SF分子的势能曲线, 通过求解双原子分子核运动的径向Schrödinger方程得到J=0 时SF分子所计算各电子态的多个振动态. 对于每一振动态, 分别计算了振动能级、惯性转动常数和离心畸变常数. 关键词： SF 势能曲线 光谱常数 分子常数     

Scaling Laws for the Multidimensional Burgers Equation with Quadratic External Potential

The reordering of the multidimensional exponential quadratic operator in coordinate-momentum space (see X. Wang, C.H. Oh and L.C. Kwek (1998). J. Phys. A.: Math. Gen. 31:4329–4336) is applied to derive an explicit formulation of the solution to the multidimensional heat equation with quadratic external potential and random initial conditions. The solution to the multidimensional Burgers equation with quadratic external potential under Gaussian strongly dependent scenarios is also obtained via the Hopf-Cole transformation. The limiting distributions of scaling solutions to the multidimensional heat and Burgers equations with quadratic external potential are then obtained under such scenarios. AMS Subject Classifications: 60G60, 60G15, 62M15, 60H15     

Kinetics of residual gas adsorption on Ge(1 1 1) surface in low-energy electron backscattering

Low-energy (0.4-1.2 eV) electron backscattering is applied for the investigation of kinetics of residual gas adsorption effect on the concentration and energy positions of surface electron states of Ge(1 1 1) surface. Chemosorption of residual gas molecules on Ge(1 1 1) at P ∼ 10⁻⁷ Pa and room temperature is shown to be most active during the first 48 h. Low concentration of dangling valence bonds on the reconstructed Ge(1 1 1) (2 × 8) surface is shown to determine its low activity to chemosorption.