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Title: Non-adiabatic dynamics investigation of the radiationless decay mechanism of trans-urocanic acid in the S{sub 2} state

Abstract

The trans-urocanic acid, a UV chromophore in the epidermis of human skin, was found to exhibit a wavelength dependent isomerization property. The isomerization quantum yield to cis-urocanic is greatest when being excited to the S{sub 1} state, whereas exciting the molecule to the S{sub 2} state causes almost no isomerization. The comparative photochemical behavior of the trans-urocanic on the S{sub 1} and S{sub 2} states continues to be the subject of intense research effort. This study is concerned with the unique photo-behavior of this interesting molecule on the S{sub 2} state. Combining the on-the-fly surface hopping dynamics simulations and static electronic structure calculations, three decay channels were observed following excitation to the S{sub 2} state. An overwhelming majority of the molecules decay to the S{sub 1} state through a planar or pucker characterized minimum energy conical intersection (MECI), and then decay to the ground state along a relaxation coordinate driven by a pucker deformation of the ring. A very small fraction of molecules decay to the S{sub 1} state by a MECI characterized by a twisting motion around the CC double bond, which continues to drive the molecule to deactivate to the ground state. The latter channel is related withmore » the photoisomerization process, whereas the former one will only generate the original trans-form products. The present work provides a novel S{sub 2} state decay mechanism of this molecule, which offers useful information to explain the wavelength dependent isomerization behavior.« less

Authors:
 [1];  [2]; ;  [1]
  1. State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22679003
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 145; Journal Issue: 4; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DOUBLE BONDS; ELECTRONIC STRUCTURE; EXCITATION; GROUND STATES; ISOMERIZATION; MOLECULES; RADIATIONLESS DECAY

Citation Formats

Zhao, Li, University of the Chinese Academy of Sciences, Beijing 100049, Zhou, Pan-Wang, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn, and Zhao, Guang-Jiu, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn. Non-adiabatic dynamics investigation of the radiationless decay mechanism of trans-urocanic acid in the S{sub 2} state. United States: N. p., 2016. Web. doi:10.1063/1.4959131.
Zhao, Li, University of the Chinese Academy of Sciences, Beijing 100049, Zhou, Pan-Wang, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn, & Zhao, Guang-Jiu, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn. Non-adiabatic dynamics investigation of the radiationless decay mechanism of trans-urocanic acid in the S{sub 2} state. United States. doi:10.1063/1.4959131.
Zhao, Li, University of the Chinese Academy of Sciences, Beijing 100049, Zhou, Pan-Wang, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn, and Zhao, Guang-Jiu, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn. Thu . "Non-adiabatic dynamics investigation of the radiationless decay mechanism of trans-urocanic acid in the S{sub 2} state". United States. doi:10.1063/1.4959131.
@article{osti_22679003,
title = {Non-adiabatic dynamics investigation of the radiationless decay mechanism of trans-urocanic acid in the S{sub 2} state},
author = {Zhao, Li and University of the Chinese Academy of Sciences, Beijing 100049 and Zhou, Pan-Wang, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn and Zhao, Guang-Jiu, E-mail: pwzhou@dicp.ac.cn, E-mail: gjzhao@dicp.ac.cn},
abstractNote = {The trans-urocanic acid, a UV chromophore in the epidermis of human skin, was found to exhibit a wavelength dependent isomerization property. The isomerization quantum yield to cis-urocanic is greatest when being excited to the S{sub 1} state, whereas exciting the molecule to the S{sub 2} state causes almost no isomerization. The comparative photochemical behavior of the trans-urocanic on the S{sub 1} and S{sub 2} states continues to be the subject of intense research effort. This study is concerned with the unique photo-behavior of this interesting molecule on the S{sub 2} state. Combining the on-the-fly surface hopping dynamics simulations and static electronic structure calculations, three decay channels were observed following excitation to the S{sub 2} state. An overwhelming majority of the molecules decay to the S{sub 1} state through a planar or pucker characterized minimum energy conical intersection (MECI), and then decay to the ground state along a relaxation coordinate driven by a pucker deformation of the ring. A very small fraction of molecules decay to the S{sub 1} state by a MECI characterized by a twisting motion around the CC double bond, which continues to drive the molecule to deactivate to the ground state. The latter channel is related with the photoisomerization process, whereas the former one will only generate the original trans-form products. The present work provides a novel S{sub 2} state decay mechanism of this molecule, which offers useful information to explain the wavelength dependent isomerization behavior.},
doi = {10.1063/1.4959131},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 4,
volume = 145,
place = {United States},
year = {2016},
month = {7}
}