| Dynamics of Triplet-State Photochemistry of Pentanal: Mechanisms of Norrish I, Norrish II, and H Abstraction Reactions | |
| Shemesh, Dorit1,2; Lan, Zhenggang3,4; Gerber, R. Benny1,2,5 | |
| 2013-11-21 | |
| 发表期刊 | JOURNAL OF PHYSICAL CHEMISTRY A
 |
| 卷号 | 117期号:46页码:11711-11724 |
| 摘要 | ABSTRACT: The photochemistry of aldehydes in the gas phase has been the topic of extensive studies over the years. However, for all but the smallest aldehydes the dynamics of the processes is largely unknown, and key issues of the mechanisms are open. In this article, the photochemistry of pentanal is studied by dynamics simulation using a semiempirical MRCI code for the singlet and triplet potential energy surfaces involved. The simulations explore the processes on the triplet state following intersystem crossing from the initially excited singlet. Test simulations show that the photochemistry takes place on the adiabatic triplet surface only and that no nonadiabatic transitions occur to the other triplets. The main findings include the following: (1) Norrish type I and type II reactions and H detachment have been observed. (2) The time scales of Norrish type I and Norrish type II reactions are determined: Norrish type I reaction tends to occur in the time scale below 10 ps, whereas the Norrish type II reaction is mostly pronounced after 20 ps. The factors affecting the time scales are analyzed. (3) The relative yield for Norrish type I and type II reactions is 34% and 66%, which is close to the experimental observed ones. Bond orders and Mulliken partial charges are computed along the trajectories and provide mechanistic insights. The results throw light on the time scales and mechanisms and competition between different channels in aldehyde photochemistry. It is suggested that direct dynamics simulations using semiempirical potentials can be a very useful tool for exploring the photochemistry of large aldehydes, ketones, and related species. ; The photochemistry of aldehydes in the gas phase has been the topic of extensive studies over the years. However, for all but the smallest aldehydes the dynamics of the processes is largely unknown, and key issues of the mechanisms are open. In this article, the photochemistry of pentanal is studied by dynamics simulation using a semiempirical MRCI code for the singlet and triplet potential energy surfaces involved. The simulations explore the processes on the triplet state following intersystem crossing from the initially excited singlet. Test simulations show that the photochemistry takes place on the adiabatic triplet surface only and that no nonadiabatic transitions occur to the other triplets. The main findings include the following: (1) Norrish type I and type II reactions and H detachment have been observed. (2) The time scales of Norrish type I and Norrish type II reactions are determined: Norrish type I reaction tends to occur in the time scale below 10 ps, whereas the Norrish type II reaction is mostly pronounced after 20 ps. The factors affecting the time scales are analyzed. (3) The relative yield for Norrish type I and type II reactions is 34% and 66%, which is close to the experimental observed ones. Bond orders and Mulliken partial charges are computed along the trajectories and provide mechanistic insights. The results throw light on the time scales and mechanisms and competition between different channels in aldehyde photochemistry. It is suggested that direct dynamics simulations using semiempirical potentials can be a very useful tool for exploring the photochemistry of large aldehydes, ketones, and related species. |
| 文章类型 | Article |
| 学科领域 | 仿真与模拟 |
| WOS标题词 | Science & Technology ; Physical Sciences |
| DOI | 10.1021/jp401309b |
| 关键词[WOS] | WAVELENGTH-DEPENDENT PHOTOLYSIS ; INITIO MOLECULAR-DYNAMICS ; PHOTOINDUCED NONADIABATIC DYNAMICS ; VIBRATIONAL OVERTONE EXCITATIONS ; POTENTIAL-ENERGY SURFACES ; PHOTOIONIZATION DYNAMICS ; SEMIEMPIRICAL METHODS ; CARBONYL-COMPOUNDS ; ELECTRONIC STATES ; PROTON-TRANSFER |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS研究方向 | Chemistry ; Physics |
| WOS类目 | Chemistry, Physical ; Physics, Atomic, Molecular & Chemical |
| WOS记录号 | WOS:000327557100013 |
| 引用统计 | |
| 文献类型 | 期刊论文 |
| 条目标识符 | http://ir.qibebt.ac.cn/handle/337004/1631 |
| 专题 | 蛋白质设计研究组 |
| 作者单位 | 1.Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel 2.Hebrew Univ Jerusalem, Fritz Haber Ctr Mol Dynam, IL-91904 Jerusalem, Israel 3.Chinese Acad Sci, Qingdao Inst Bioenergy & Bioprocess Technol, Key Lab Biobased Mat, Qingdao 266101, Peoples R China 4.Chinese Acad Sci, Qingdao Inst Bioenergy & Bioprocess Technol, Qingdao Key Lab Solar Energy Utilizat & Energy St, Qingdao 266101, Peoples R China 5.Univ Calif Irvine, Dept Chem, Irvine, CA 92597 USA |
| 推荐引用方式 GB/T 7714 | Shemesh, Dorit,Lan, Zhenggang,Gerber, R. Benny. Dynamics of Triplet-State Photochemistry of Pentanal: Mechanisms of Norrish I, Norrish II, and H Abstraction Reactions[J]. JOURNAL OF PHYSICAL CHEMISTRY A,2013,117(46):11711-11724. |
| APA | Shemesh, Dorit,Lan, Zhenggang,&Gerber, R. Benny.(2013).Dynamics of Triplet-State Photochemistry of Pentanal: Mechanisms of Norrish I, Norrish II, and H Abstraction Reactions.JOURNAL OF PHYSICAL CHEMISTRY A,117(46),11711-11724. |
| MLA | Shemesh, Dorit,et al."Dynamics of Triplet-State Photochemistry of Pentanal: Mechanisms of Norrish I, Norrish II, and H Abstraction Reactions".JOURNAL OF PHYSICAL CHEMISTRY A 117.46(2013):11711-11724. |
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