Total cross sections for electrons scattering from C_2F_4 and SO_2 at 30-5000 eV: considering the geometric shielding effect

Considering the changes of the geometric shielding effect in a molecule as the incident electron energy varing, an empirical fraction, which is dependent on the incident electron energy, is presented. Using this empirical fraction, the total cross sections (TCSs) for electrons scattering from complex polyatomic molecules C2F4 and SO2 are calculated over a wide energy range from 30 to 5000 eV together with the additivity rule model at Hartree-Fock level. In the TCS calculations, the atoms are presented by the spherical complex optical potential, which is composed of static, exchange, polarization and absorption contributions. The quantitative TCSs above 100 eV are in good agreement with those obtained by experiments and other theories. It is proved that the empirical fraction, which exhibits the TCS contributions of shielded atoms in a molecule at different energies, is reasonable.     

中高能量电子被NO_2和SO_2分子散射总截面的研究

用模型势方法对正电子与氪、氙原子散射角分布进行了系统计算，通过对算得的微分截面（散射角从２０°－１６０°）的数据分析，结合作者以前对正电子与氦、氖、氩原子散射角分布的研究结论，总结出了低能正电子与稀有气体原子散射角分布规律     

An Empirical Formula Approach to Total Cross Sections for Electron Scattering on Polyatomic Molecules

Considering the real experimental process of e-molecule scattering a new empirical formula has been developed to calculate the total cross sections （TOSs） for electron scattering on polyatomic molecules （CH4, C2H2, CH3OH and CH3F）. The present results are compared with other available theoretical results and experimental data. The new formula incorporates an energy factor f（E） to represent the elastic and inelastic changing process during experiments. It depends on no adjustable parameters and has also extended the validity of the empirical approaches to lower energy range further.     

Absolute Differential Cross Sections for Elastic Scattering of Electrons from CO at Intermediate and High Energies

The additivity rule model together with the complex optical model potential correlated by the concept of bonded atoms, which considers the overlapping effect of electron clouds between two atoms in a molecule, is firstly employed to calculate the absolute differential cross sections for electrons scattered by carbon monoxide at intermediate and high energies at the Hartree-Fock level. A comparison of elastic differential cross section results, obtained by using the correlated complex optical model potential, with the available experimental data,shows a significant improvement over the uncorrelated ones. The differential cross sections obtained by using thecorrelated complex optical model potential are in very good agreement with the experimental data. It is shown that the additivity rule model together with the correlated complex optical model potential is suitable for the calculations of the absolute differential cross sections of e-CO scattering.     

100～5 000 eV下电子被等电子(Z=10)分子CH4、H2O、HF及NH3散射的总截面计算

利用可加性规则,使用Roothaan-Hartree-Fock波函数,在100～5 000 eV下首次采用由束缚原子概念修正过的复光学势,对电子被等电子(Z=10)分子CH4、H2O、HF和NH3散射的总截面进行了计算.束缚原子不同于自由原子之处,是束缚原子考虑了在不同分子中电子云的不同重叠,将计算结果与实验及其它计算结果进行了比较.结果表明,利用被束缚原子概念修正过的复光学势及可加性规则进行计算,其结果的精度要比利用未被束缚原子概念修正过的复光学势及可加性规则进行计算得到的结果好.     

IBr分子含时波包的理论探究

本文主要对IBr分子的飞秒含时光电子能谱进行了模拟计算.运用含时量子波包方法,对不同延迟时间的光电子能谱进行模拟计算与理论分析.应用波包和光诱导势理论,对光电子能谱共同的两峰系特征及多峰现象给予合理解释.光电子能谱的峰值随延迟时间的增加而递减现象,是由于波包在势能面上因分子解离发散,使整个波包在势能曲线上的振荡递减造成的.研究表明：波包的传播是一个能量减弱的过程;跃迁过程中不同电离通道之间的竞争,也对能谱存在一定的影响.     

XF2(X=B,N)分子基态的结构与势能函数

基于Gaussian03计算软件利用QCISD方法,选用不同基组对XF₂(X=B,N)分子基态结构进行了几何优化,在此基础上选出最优基组D95(df,pd)和D95+(df,pd)分别对BF₂和NF₂分子的谐振频率、力常数等进行了计算.推导出XF₂(X=B,N)分子基态的多体展式势能函数,同时根据势能函数绘制了XF₂(X< 关键词： 2')" href="#">BF₂ 2')" href="#">NF₂ 结构 势能函数     

从头计算研究CH3C(O)OSSOC(O)CH3的构型和能量

采用从头计算B3LYP,MP3和MP4方法结合Aug-cc-pVDZ基组研究了CH₃C(O)OSSOC(O)CH₃最稳定的五种构象及其阳离子构型.理论计算了五种稳定构象的转动常数和偶极矩;运用电子传播子理论P3近似方法计算稳定构象外价壳层轨道的电离能,计算结果与光电子能谱实验结果符合的较好.根据构象的相对能量以及理论模拟电离能谱和实验光电子能谱之间的比较,说明在气相光电子能谱实验中至少存在两种构象.与中性构型相比,电离后的五种阳离子构型均发生了明显的结构弛豫,尤 关键词： 构象 电离能 相对能量 光电子能谱     

用MRCI方法研究CS+同位素离子X2Σ+和A2Π态的光谱常数与分子常数

利用内收缩多参考组态相互作用方法和价态范围内的最大相关一致基aug-cc-pV6Z, 在0.05—0.60 nm的核间距范围内计算了CS⁺离子X²Σ+和A²Π态的势能曲线. 利用CS⁺离子的势能曲线并在同位素质量修正的基础上, 拟合出了X²Σ+和A²Π态的同位素离子^{1 关键词： 同位素识别 势能曲线 光谱常数 分子常数}     

从头计算研究超共轭效应对2-氯乙醇电子波函数的影响

运用从头算的B3LYP和MP2方法研究了2-氯乙醇分子五种构象的电子结构．在自然键轨道理论分析的基础上讨论了存在的分子内氢键和超共轭作用对构象稳定性的影响,结果说明后者是构象稳定性的主要因素．结合电子动量谱学研究了这种超共轭作用对最外价壳层轨道(HOMO)的电子波函数的影响,演示了动量空间HOMO波函数的不同．