高等学校化学学报 ›› 1996, Vol. 17 ›› Issue (12): 1904.

• 论文 • 上一篇    下一篇

H+NF2→NF(a)+HF反应的从头算研究

郭敬忠, 邓从豪   

  1. 山东大学理论化学研究室, 济南, 250100
  • 收稿日期:1995-12-21 出版日期:1996-12-24 发布日期:1996-12-24
  • 通讯作者: 郭敬忠,男,31岁,博士研究生,副教授.
  • 作者简介:郭敬忠,男,31岁,博士研究生,副教授.
  • 基金资助:

    国家自然科学基金

Ab Initio study of H+HF2→NF(a)+HF Reaction

GUO Jing-Zhong, DENG Cong-Hao   

  1. Theoretical Chemistry Group, Shandong University, Jinan, 250100
  • Received:1995-12-21 Online:1996-12-24 Published:1996-12-24

摘要: 本文用量子化学从头算法对H+NF2→NF(a)+HF反应进行了理论研究,采用MP2(FULL)/6-31G(d)方法计算了反应物、产物、中间体和过渡态的构型参数和振动频率,然后用Gaussian-2理论计算了各物种的精确能量,计算结果表明:反应在单重态势能面上进行,电子激发态NF(a)通过复合-消除机理产生,用G2理论计算298K下反应的焓变为-119.4kJ/mol,过渡态比反应物能量低98.4kJ/mol.中间体HNF2是势能面的最低点,比反应物的能量低313.5kJ/mol.

关键词: 从头算法, 反应机理, Gaussian-2理论

Abstract: The reaction of H+NF2→NF(a)+HF was studied by using ab initio methods.The geometries and frequencies for all species were calculated at MP2(FULL)/6-31G(d)level of theory.The energies of all species were further calculated using Gaussian 2 theory.The result implies that the reaction proceeds via an addition-elimination mechanism on the lowest singlet potential surface.The addition processes form HNF2 molecules as the intermediates without barriers,The metastable radical NF(a)is formed by unimolecular HFelimination reactions via three-centered transition state.The best estimation of the heat of reaction is -119.4kJ/mol at 298 K. The energy of the transition state forming NF(a) is 98.4 kJ/mol lower than the reactants,The intermediate HNF2 with an energy of 313.5kJ/mol lower than the reactants is the lowest point on the potential surface,Since the overall activation energy is negative,the title reaction is expected to be a good chemical source of NF(a)radical which was found experimentally.

Key words: Ab initio calculation, Reaction mechanism, Gaussian-2 theory

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