We report a theoretical study of electronic excitation in CH₃Cl and CF₃Cl by electron impact. Momentum-transfer-dependent generalized oscillator strengths (GOSs) are calculated for transitions to low-lying excited singlet-states at the equation-of-motion coupled-cluster singles and doubles level. The influence of molecular vibration is taken into account in the calculation. The theoretical results show reasonable overall agreement with experimental data reported in the literature. The shapes of the GOS profiles reveal that the 1 ¹E state of CH₃Cl has a valence-Rydberg mixed nature, while that of CF₃Cl is of a predominant C–Cl antibonding character. A comparison with the experimental GOSs of CH₃Cl provides unambiguous evidence that the 3pe state is lower in energy than the 3pa₁ state. Optical oscillator strengths are also calculated and comparison is made with available experimental and other theoretical results.

中文翻译：

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CH3Cl 和 CF3Cl 低电子激发的广义振荡器强度的理论研究

我们报告了通过电子碰撞在 CH ₃ Cl 和 CF ₃ Cl 中进行电子激发的理论研究。计算动量传递相关的广义振荡器强度 (GOS)，以在运动方程耦合簇单峰和双峰水平上过渡到低位激发单重态。计算中考虑了分子振动的影响。理论结果与文献中报道的实验数据显示出合理的总体一致性。GOS 曲线的形状表明， CH _{3 Cl 的 1} ¹ E 态具有价-里德伯混合性质，而 CF ₃ Cl 的 1 1 E 态具有主要的 C-Cl 反键特征。_{与CH 3}实验GOS的比较Cl 提供了明确的证据表明 3pe 状态的能量低于 3pa ₁状态。还计算了光学振荡器的强度，并与可用的实验和其他理论结果进行了比较。