A re‐examination of the S0→S1 excitation spectrum of dimethylaniline
A re‐examination of the S0→S1 excitation spectrum of dimethylaniline
复制标题
二甲基苯胺S0→S1激发光谱的重新检验
DOI：
10.1063/1.469967
复制
发表时间：
1995
影响因子：
4.4
通讯作者：
R. Gordon
中科院分区：
文献类型：
--
作者：
R. Weersink;S. Wallace;R. Gordon
对N，N-二甲基苯胺（DMA）及其衍生物的S 0 →S1跃迁进行了新的归属。在DMA-h6和DMA-d 6中观察到的低频带和长的Franck-Condon包络被归属于氨基的耦合甲基扭转模式，而不是氨基取代基围绕C-N键的扭转。这种新的分配是一致的激发带的频率的变化后，氘代的甲基和其他烷基苯胺的激发光谱中观察到的强烈的起源过渡。通过模拟DMA-h6和DMA-d 6的激发光谱确认了该归属，计算的势能面参数确定为V3=148.0±0.5 cm−1，V+=−31.6±0.5 cm−1，V−=8.5±0.5 cm−1，V6=−15±0.5 cm−1。通过Franck-Condon分析，确定了弱原点跃迁是由于S1扭转最小值相对于基态下相应的最小值沿啮合坐标移动了沿着40°所致。
A new assignment for the S0→S1 transition of N,N‐dimethylaniline (DMA) and related derivatives is presented. The low frequency bands and long Franck–Condon envelope observed in DMA‐h6 and DMA‐d6 are assigned to the coupled methyl torsion mode of the amino group, not to torsion of the amino substituent about the C–N bond. This new assignment is consistent with the change in frequency of the excitation bands upon deuteration of the methyl groups and the strong origin transitions observed in the excitation spectra of other alkyl anilines. The assignment was confirmed by simulations of the excitation spectra of DMA‐h6 and DMA‐d6, with parameters of the calculated potential energy surface determined to be V3=148.0±0.5 cm−1, V+=−31.6±0.5 cm−1, V−=8.5±0.5 cm−1, and V6=−15±0.5 cm−1. By Franck–Condon analysis, it was determined that the weak origin transition is due to the shifting of the S1 torsion minimum by 40° along the gearing coordinate relative to the corresponding minimum in the ground state.