SO自由基X3∑-, a1△和A'3△电子态的光谱常数

采用内收缩多参考组态相互作用(MRCI)方法计算了SO自由基X³∑^-, a¹△和A^'3△电子态的势能曲线. 采用Davidson修正避免由于MRCI方法本身的大小一致性缺陷产生的误差. 进一步考虑了相对论修正和核价相关修正对势能曲线的影响. 相对论修正是利用二阶Douglas-Kroll 哈密顿近似在cc-pV5Z基组水平进行的;同时核价相关修正是在cc-pCVDZ基组水平进行的. 为了提高计算精度,利用两点能量外推法,将各能量外推至完全极限处,得到外推后的势能曲线,再对势能曲线进行拟合,得到各种水平下三个电子态的光谱常     

AlN,GaN和InN分子基态的结构和解析势能函数(英文)

采用密度泛函理论的B3LYP/6-311+G(3df)方法优化计算了A1N,GaN和InN分子基态的平衡结构、振动频率和离解能.根据原子分子反应静力学原理,导出了A1N,GaN和InN分子的合理离解极限,利用Murrell-Sorbie势能函数和从头算结果得到基态相应的解析势能函数并由光谱数据和解析势能函数的关系计算了基态的光谱数据(α_e,B_e,ω_e和ω_ex_e),计算结果与实验数据符合得相当好.     

Theoretical investigations of spectroscopic parameters and molecular constants for electronic ground state of Cl2 and its isotopes

The potential energy curve of the Cl 2(X1Σg+) is investigated by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in combination with the largest correlation-consistent basis set, aug-cc-pV6Z, in the valence range. The theoretical spectroscopic parameters and the molecular constants of three isotopes, 35Cl2, 35Cl37Cl and 37Cl2, are studied. For the 35Cl2 (X1Σg+), the values of D0 , De , Re , ωe , ωeχe , αe and Be are obtained to be 2.3921 eV, 2.4264 eV, 0.19939 nm, 555.13 cm-1 , 2.6772 cm-1 , 0.001481 cm-1 and 0.24225 cm-1 , respectively. For the 35Cl37Cl(X1Σg+), the values of D0 , De , Re , ωe , ωeχe , αe and Be are calculated to be 2.3918 eV, 2.4257 eV, 0.19939 nm, 547.68 cm-1 , 2.6234 cm-1 , 0.00140 cm-1 and 0.23572 cm-1 , respectively. And for the 37C2 (X1Σg+), the values of D0 , De , Re , ωe , ωeχe , αe and Be are obtained to be 2.3923 eV, 2.4257 eV, 0.19939 nm, 540.06 cm-1 , 2.5556 cm-1 , 0.00139 cm-1 and 0.22919 cm-1 , respectively. These spectroscopic results are in good agreement with the available experimental data. With the potential of Cl2 molecule determined at the MRCI/aug-cc-pV6Z level of theory, the total of 59 vibrational states is predicted for each isotope when the rotational quantum number J equals zero (J = 0). The theoretical vibrational levels, classical turning points, inertial rotation and centrifugal distortion constants are determined when J = 0, which are in excellent accordance with the available experimental findings.     

中高能正电子被CO,HCl,NH3及SiH4散射的总截面

利用可加性规则,使用Hartree-Fock波函数,采用由束缚原子概念修正过的复光学势(由静电势、极化势及吸收势三部分组成),在30-3000eV内对正电子被CO,HCl,NH3和SiH4散射的总截面进行了计算,且将计算结果与实验结果及其他理论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,所得结果与实验结果的符合程度要比利用未被束缚原子概念修正的复光学势及可加性规则进行计算得到的结果好很多.因此,在复光学势中采用束缚原子概念可提高正电子被分子散射的总截面的计算准确度.     

30-3000eV的正电子被O2、H2O及CH4散射的总截面计算

使用可加性规则，在Hartree-Fock水平上计算了30-3000eV的正电子被三个分子（O2、H2O及CH4）散射的总截面。计算正电子被三个分子散射的总截面时，首次使用了被束缚原子概念修正过的复光学势（这一复光学势考虑了分子中两个原子间的电子云重叠效应）。将正电子被这三个分子散射的总截面计算结果与实验结果及其它理论计算结果进行了比较，结果显示出在30-3000eV内，文中的计算结果与实验结果及其它理论计算结果具有较好的一致性。因此，可加性规则与修正后的复光学势相结合，完全适用于正电子被分子散射的总截面的计算。     

Li_2分子X~1∑_g~ ,A~1∑_u~ 和B~1∏_u态的势能函数

使用SAC/SAC-CI方法,利用D95、D95(d)、6-311g以及6-311g(d)等基组,对Li2分子的基态(X1∑g )、第一激发态(A1∑u )及第二激发态(B1∏u)的平衡结构和谐振频率进行了优化计算。通过对四个基组的计算结果的比较,得出了D95(d)基组为四个基组中的最优基组的结论;使用D95(d)基组,利用SAC的GSUM(Group Sum of Operators)方法对基态(X1∑g )、SAC-CI的GSUM方法对激发态(A1∑u 和B1∏u)进行单点能扫描计算,用正规方程组拟合Murrell-Sorbie函数,得到了相应电子态的完整势能函数;从得到的势能函数计算了与基态(X1∑g )、第一激发态(A1∑u )和第二激发态(B1∏u)相对应的光谱常数(Be,αe,ωe和ωexe),结果与实验数据较为一致。其中,基态、第一激发态与实验数据吻合得非常好。     

A new semi-empirical formula for total cross sections of electron scattering from triatomic molecules at 30—5000 eV

Total cross sections (TCSs) for electrons scattering from molecules over a wide energy range are widely used in gaseous lasers, astrophysics, plasma physics, atmospheric physics, and chemical physics, etc.. TCS values repro- duced by analytical or empirical expressions accurately are very useful in computational work related with these applications. Because electron-molecule scattering is a much more complex problem than the corresponding electron-atom scattering, in order to get more accura…     

一种计算中、高能电子被分子散射总截面的修正势方法

在考虑分子内成键原子间的电子云重叠效应的基础上，提出了一种能够在中、高能区准确计算“电子-分子”散射总截面的修正势方法.利用可加性规则及Hartree-Fock波函数，使用这一修正过的复光学势，在30—5000eV内对电子被4个等电子(Z=18)分子(HCl，H₂S，PH₃和SiH₄)散射的总截面进行了计算，并将理论计算值与实验结果及其他理论值进行了比较.结果表明，利用这一修正过的复光学势及可加性规则进行计算，所得理论值与实验结果更为接近. 关键词： 电子散射 总截面 可加性规则 束缚原子     

A modification potential method of calculating total cross sections of electrons scattering from complex molecules C2H6, C2F6, C6H6 and C6F6 at 100 eV-5000 eV

A complex optical model potential modified by incorporating the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is first employed to calculate the total cross sections for electrons scattering from such complex molecules as C总交叉断面 电子散射 添加规则 原子分子碰撞 电子云total cross section, electrons scattering, additivity rule, atomic and molecular collisionProject supported by the National Natural Science Foundation of China (Grant No 10574039).2005-11-102005-11-102005-11-30A complex optical model potential modified by incorporating the concept of bonded atom, which takes into consideration the overlapping effect of electron clouds between two atoms in a molecule, is first employed to calculate the total cross sections for electrons scattering from such complex molecules as C2H6, C2F6, C6H6 and C6F6 using the aclditivity rule model at Hartree-Fock level over the energy range from 100 eV to 5000 eV. The total cross sections are quantitatively compared with those obtained by experiments wherever available, and they are in good agreement with each other over a wide energy range. It is shown that the modified potential together with the additivity rule model is completely suitable for the calculation of total cross sections of electrons scattering from such complex molecules as C2H6, C2F6, C6H6 and C6F6 above 200 eV-300 eV.     

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.