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Comparative studies of the trans-to-cis photoisomerizations of azobenzene and a bridged azobenzene
发布时间：2025-04-30
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- 发布时间：
- 2025-04-30
- 论文名称：
- Comparative studies of the trans-to-cis photoisomerizations of azobenzene and a bridged azobenzene
- 发表刊物：
- The Journal of Physical Chemistry A
- 摘要：
- Using density-functional-based molecular dynamics simulations, we have performed comparative studies of the trans-cis isomerizations of azobenzene and bridged azobenzene (B-Ab) 5,6-dihydrodibenzo[c,g]-
[1,2]diazocine induced by nπ* electronic excitation. The quantum yields found in our calculations, 45% for the bridged azobenzene versus 25% for azobenzene, are consistent with the experiment. Both isomerization processes involve two steps: (1) Starting from the trans structure, each molecule moves on its S1 excited state potential energy surface, via rotation around the NN bond, to an avoided crossing near the S1/S0 conical intersection, where de-excitation occurs. (2) Subsequently, in the electronic ground state, there is further rotation around the NN bond, accompanied by twisting of the phenyl rings around their CN bonds, until the cis geometry is achieved. Because of its lower symmetry and smaller initial CNNC dihedral angle, the bridged azobenzene has a much shorter lifetime for the S1 excited state, about 30 fs, as compared to about 400 fs for azobenzene. However, we find that the complete isomerizations have approximately the same time scales. Although the bridging feature in trans-B-Ab does not hinder rotation around the NN bond in step 1, it makes twisting of the two phenyl rings around the CN bonds much slower in step 2.
- 合写作者：
- Chen-Wei Jiang, Rui-Hua Xie, Fu-Li Li et al.
- 卷号：
- 115
- 页面范围：
- 244
- 是否译文：
- 否
- 发表时间：
- 2011-01-01
