Substituent effects on dynamics at conical intersections: Allene and methyl allenes
文献类型：期刊论文
| 作者 | Neville, Simon P.1; Wang, Yanmei2; Boguslavskiy, Andrey E.1,3,4; Stolow, Albert1,3,4; Schuurman, Michael S.1,3 |
| 刊名 | JOURNAL OF CHEMICAL PHYSICS
 |
| 出版日期 | 2016-01-07 |
| 卷号 | 144期号:1 |
| 英文摘要 | We report a joint experimental and theoretical study on the ultrafast excited state dynamics of allene and a series of its methylated analogues (1,2-butadiene, 1,1-dimethylallene, and tetramethylallene) in order to elucidate the conical intersection mediated dynamics that give rise to ultrafast relaxation to the ground electronic state. We use femtosecond time-resolved photoelectron spectroscopy (TRPES) to probe the coupled electronic-vibrational dynamics following UV excitation at 200 nm (6.2 eV). Ab initio multiple spawning (AIMS) simulations are employed to determine the mechanistic details of two competing dynamical pathways to the ground electronic state. In all molecules, these pathways are found to involve as follows: (i) twisting about the central allenic C-C-C axis followed by pyramidalization at one of the terminal carbon atoms and (ii) bending of allene moiety. Importantly, the AIMS trajectory data were used for ab initio simulations of the TRPES, permitting direct comparison with experiment. For each molecule, the decay of the TRPES signal is characterized by short (30 fs, 52 fs, 23 fs) and long (1.8 ps, 3.5 ps, [306 fs, 18 ps]) time constants for 1,2-butadiene, 1,1-dimethylallene, and tetramethylallene, respectively. However, AIMS simulations show that these time constants are only loosely related to the evolution of electronic character and actually more closely correlate to large amplitude motions on the electronic excited state, modulating the instantaneous vertical ionization potentials. Furthermore, the fully substituted tetramethylallene is observed to undergo qualitatively different dynamics, as displacements involving the relatively massive methyl groups impede direct access to the conical intersections which give rise to the ultrafast relaxation dynamics observed in the other species. These results show that the branching between the "twisting" and "bending" pathways can be modified via the selective methylation of the terminal carbon atoms of allene. The interplay between inertial and potential effects is a key to understanding these dynamical branching pathways. The good agreement between the simulated and measured TRPES confers additional confidence to the dynamical picture presented here. (C) 2016 AIP Publishing LLC. |
| WOS标题词 | Science & Technology ; Physical Sciences |
| 类目[WOS] | Chemistry, Physical ; Physics, Atomic, Molecular & Chemical |
| 研究领域[WOS] | Chemistry ; Physics |
| 关键词[WOS] | RESOLVED PHOTOELECTRON-SPECTROSCOPY ; PHOTOFRAGMENT TRANSLATIONAL SPECTROSCOPY ; EXCITED-STATE DYNAMICS ; 193 NM ; PHOTODISSOCIATION DYNAMICS ; NONADIABATIC DYNAMICS ; MOLECULAR-DYNAMICS ; PROPYNE ; 1,2-BUTADIENE ; PHOTOLYSIS |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000368617300011 |
| 公开日期 | 2016-05-09 |
| 源URL | [http://ir.wipm.ac.cn/handle/112942/9152]  |
| 专题 | 武汉物理与数学研究所_原子分子光物理研究部 |
| 作者单位 | 1.Univ Ottawa, Dept Chem, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada 2.Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China 3.Natl Res Council Canada, 100 Sussex Dr, Ottawa, ON K1A 0R6, Canada 4.Univ Ottawa, Dept Phys, 150 Louis Pasteur, Ottawa, ON K1N 6N5, Canada |
| 推荐引用方式 GB/T 7714 | Neville, Simon P.,Wang, Yanmei,Boguslavskiy, Andrey E.,et al. Substituent effects on dynamics at conical intersections: Allene and methyl allenes[J]. JOURNAL OF CHEMICAL PHYSICS,2016,144(1). |
| APA | Neville, Simon P.,Wang, Yanmei,Boguslavskiy, Andrey E.,Stolow, Albert,&Schuurman, Michael S..(2016).Substituent effects on dynamics at conical intersections: Allene and methyl allenes.JOURNAL OF CHEMICAL PHYSICS,144(1). |
| MLA | Neville, Simon P.,et al."Substituent effects on dynamics at conical intersections: Allene and methyl allenes".JOURNAL OF CHEMICAL PHYSICS 144.1(2016). |
入库方式： OAI收割
来源：武汉物理与数学研究所
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