α,β-烯酮光诱导内转换和系间窜越过程的电子结构计算和动力学模拟

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• 英文论文题名：Internal conversion and intersystem crossing in α,β-enones:a combination of electronic structure calculations and dynamics simulations
• 论文作者：曹军 ; 谢智中
• 英文论文作者：Jun Cao ; Zhi-Zhong Xie ; Guizhou Provincial Key Laboratory of Computational Nano-material Science ; Guizhou Education University ; Key Laboratory of Theoretical and Computational Photochemistry ; Ministry of Education ; College of Chemistry ; Beijing Normal University ; Department of Chemistry ; School of Chemistry ; Chemical Engineering and Life Sciences ; Wuhan University of Technology
• 年：2016
• 作者机构：贵州师范学院贵州省纳米材料模拟与计算重点实验室;北京师范大学教育部理论与计算光化学重点实验室,化学学院;武汉理工大学化学工程与生命科学学院,化学学院化学系;
• 论文关键词：内转换 ; 系间窜越 ; α ; β-烯酮
• 会议召开时间：2016-07-01
• 会议录名称：中国化学会第30届学术年会摘要集-第十九分会：化学中的量子与经典动力学
• 语种：中文
• 分类号：O621.13
• 学会代码：ZGHY
• 会议名称：中国化学会第30届学术年会-第十九分会 ; 化学中的量子与经典动力学
• 会议地点：中国辽宁大连
• 主办单位：中国化学会
• 学会名称：中国化学会
• 页数：1
• 文件大小：319k
• 原文格式：D
• 会议级别：全国

摘要

在这篇论文中,我们应用从头算电子结构计算和非绝热动力学模拟方法研究了气相反式丙烯醛和2-环戊烯酮的光诱导内转换和系间窜越过程。计算结果表明,从Franck-Condon区到第一激发电子态(S_1)极小的弛豫是一个超快过程;由于S_1态内转换到S_0态存在较大的能垒,而三重态(T_2和T_1)跟S_1态在能量上接近,因此S_1态主要发生系间窜越到达三重态。S_1/T_2/T_1三态交叉在这个S_1态失活过程中扮演重要角色,这跟之前的结论一致[1,2]。尽管这两个分子拥有类似的激发态失活途径和三重态量子产率,但是2-环戊烯醛的系间窜越速率比反式丙烯醛的偏低。分析表明,戊环导致单三态交叉区的自旋轨道耦合变小,从而降低了系间窜越速率。
The ab initio electronic structure calculations and CASSCF-based nonadiabatic dynamics simulations have been used to investigate the internal conversion and intersystem crossing(ISC) process of both trans-acrolein and 2-cyclopentenone in the gas phase. Our calculation results show that relaxation from the Franck–Condon region to an S_1 minimum is ultrafast and that the S_1 state will dominantly undergo ISC to triplet states due to the existence of significant barriers to access the S_1/S_0 points and of energetically close-lying triplet states. The S_1/T_2/T_1 intersection is observed to play an important role in population of the T_1 state, which is consistent with previous suggestions. Although evolution into triplet states involves a similar path and gives rise to a similar triplet quantum yield for these two molecules, the ISC rate of 2-cyclopentenone is lower owing to the ring constraint that results in a smaller spin–orbital coupling in the singlet–triplet crossing region.

引文

[1]Reguero,M.;Olivucci,M.;Bernardi,F.;Robb,M.A.J.Am.Chem.Soc.1994,116:2103.
    [2]Fang,W.-H.J.Am.Chem.Soc.1999,121:8376.