Theoretical Study of Valence Shell Excitation by Electron Impact in CCl<sub>4</sub>
Theoretical Study of Valence Shell Excitation by Electron Impact in CCl<sub>4</sub>
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CCl<sub>4</sub>中电子碰撞价电子层激发的理论研究
DOI：
10.1021/acs.jpca.2c08619
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Takahashi Masahiko
中科院分区：
文献类型：
--
作者：
Watanabe Noboru;Takahashi Masahiko
本文报道了用高能电子碰撞对CCl_4的价层激发的理论研究。在运动方程耦合团簇单分子和双分子水平上计算了分子的广义振子强度。为了阐明核动力学对电子激发截面的影响，计算中考虑了分子振动的影响。在与最近的实验数据比较的基础上，对光谱特征进行了重新解释，发现Cl 3p非键轨道到σ* 反键轨道7a1和8t2的激发在激发能低于1.9eV时起主导作用.此外，计算表明，由于不对称伸缩振动引起的分子结构扭曲显着影响小动量转移时的价激发，其中偶极跃迁的贡献占主导地位。这表明振动效应对CCl_4光解过程中Cl的生成有很大的影响。
This paper reports a theoretical study of valence shell excitation in CCl4by high-energy electron impact. Generalized oscillator strengths are calculated for the molecule at the equation-of-motion coupled-cluster singles and doubles level. To elucidate the influence of nuclear dynamics on electron excitation cross-sections, the effects of molecular vibration are included in the calculation. Based on a comparison with recent experimental data, several reassignments of spectral features are made, and it is found that excitations from the Cl 3p nonbonding orbitals to σ* antibonding orbitals, 7a1and 8t2, play dominant roles below the excitation energy of ∼9 eV. Furthermore, the calculations reveal that distortion of the molecular structure due to the asymmetric stretching vibration significantly affects the valence excitations at small momentum transfers, where contributions from dipole transitions are dominant. It indicates that vibrational effects have a considerable influence on Cl formation in the photolysis of CCl4.