First-principles C band absorption spectra of SO2 and its isotopologues.
First-principles C band absorption spectra of SO2 and its isotopologues.
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SO2 及其同位素体的第一性原理 C 谱带吸收光谱。
作者：
B. Jiang;Praveen Kumar;J. Kłos;M. Alexander;B. Poirier;Hua Guo
利用新近发展的两个电子态的从头算势能面和相应的跃迁偶极面，计算了SO2的~（32）S，~（33）S，~（34）S和~（36）S同位素的C <$B ~（21）<$X <$1A1紫外吸收谱的低能部分.计算了SO_2（X ~ 1A_1）分子各种振转态的态分辨吸收光谱。当这些激发振转态的贡献包括在内，热平均光谱加宽，但保持其关键特征。发现与实验吸收光谱的极好的协议，验证PES的准确性。吸收峰的同位素位移与能量成线性关系，与实验结果符合较好。
The low-energy wing of the C∼B21←X∼1A1 absorption spectra for SO2 in the ultraviolet region is computed for the 32S,33S,34S and 36S isotopes, using the recently developed ab initio potential energy surfaces (PESs) of the two electronic states and the corresponding transition dipole surface. The state-resolved absorption spectra from various ro-vibrational states of SO2(X∼1A1) are computed. When contributions of these excited ro-vibrational states are included, the thermally averaged spectra are broadened but maintain their key characters. Excellent agreement with experimental absorption spectra is found, validating the accuracy of the PESs. The isotope shifts of the absorption peaks are found to increase linearly with energy, in good agreement with experiment.