高等学校化学学报

高等学校化学学报 ›› 2011, Vol. 32 ›› Issue (7): 1588.

• 研究论文 • 上一篇    下一篇

乙醇醛光解离机理的理论研究

慈成刚, 段雪梅, 刘靖尧, 孙家钟   

  1. 吉林大学理论化学研究所, 理论化学计算国家重点实验室, 长春 130021
  • 收稿日期:2010-09-02 修回日期:2010-10-19 出版日期:2011-07-10 发布日期:2011-06-02
  • 通讯作者: 刘靖尧 E-mail:ljy121@jlu.edu.cn
  • 基金资助:

    国家自然科学基金(批准号: 20303007, 20973077)和教育部新世纪优秀人才支持计划(NCET)资助.

Theoretical Studies on Photodissociation Mechanism of Glycoladehyde

CI Cheng-Gang, DUAN Xue-Mei, LIU Jing-Yao*, SUN Chia-Chung   

  1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China
  • Received:2010-09-02 Revised:2010-10-19 Online:2011-07-10 Published:2011-06-02
  • Contact: LIU Jing-Yao E-mail:ljy121@jlu.edu.cn
  • Supported by:

    国家自然科学基金(批准号: 20303007, 20973077)和教育部新世纪优秀人才支持计划(NCET)资助.

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摘要： 采用多参考态方法, 在CASPT2//CASSCF/6-311+G(2df, 2p) 水平上计算了乙醇醛(HOCH2CHO)分子在三个最低电子态(S0、S1和T1)上驻点的电子结构和解离势能面。结合势能面交叉点，探讨了HOCH2CHO与波长有关的光解离机理，分析了可能的光解离产物。结果表明, 在实验光解波长240 – 400 nm的激发下，HOCH2CHO分子主要发生S1态上的解离反应或通过S0和S1态之间的振动相互作用驰豫到基态，随之发生基态解离反应。C-C键断裂生成基态光解产物HOCH2 (2A′)+ HCO (2A′)是最主要的反应途径；而在一定波长下，生成CH3OH + CO的基态协同反应、脱醛基氢及脱羟基通道都是能量上可行的反应途径。本文的计算结果和实验观察一致。

关键词: 反应机理, 乙醇醛, 光解离, 势能面

Abstract: The electronic structures of the stationary points and dissociation potential energy surfaces (PES) of glycolaldehyde （HOCH2CHO） in the lowest three electronic states (S0, S1 and T1) have been calculated at the CASPT2//CASSCF/6-311+G(2df, 2p) level of theory by using the multi-reference state method. Combining with the surface intersection points, the wavelength-dependent photolysis mechanisms leading to probable photolysis products have been elucidated. It is shown that in the experimental photolysis wavelength range of 240 – 400 nm, the HOCH2CHO molecule mainly occurs the dissociation reactions on the S1 surface or decays to the ground state via the S0 and S1 vibronic interaction, followed by S0 dissociation reactions. The C-C bond fission to yield ground-state products HOCH2 (2A′）+ HCO (2A′) is the dominant pathway, while in the certain wavelength range, the S0 concerted channel to produce CH3OH (A′) + CO (A1), H-elimination of the aldehyde group and OH-elimination channels are also energetically accessible. The present calculated results show good agreement with the experimental observations.

Key words: Reaction mechanism, Glycolaldehyde, Photodissociation, Potential energy surface

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