## 抄録

Ab initio contracted spin-orbit configuration interaction (SOCI) calculations have been carried out to obtain potential energy surfaces of ^{3}Q_{0} and ^{1}Q_{1} excited states of methyl iodide as functions of all the geometrical parameters except for the three C-H stretches. The results are fitted to six-dimensional diabatic potential functions and their couplings. Classical trajectory calculations have been performed using these potential functions. The rotation of the CH_{3} product in the I channel has been calculated to be perpendicular to the top axis and to have a peak at N = 5 and extend up to N = 8, whereas it is cold in the I* channel, in good agreement with recent experiments. The CH_{3} rotation is excited by the time trajectories arrive at the conical intersection region; this excitation is retained in the I-channel product because the ^{1}Q_{1} surface has a small bending force constant outside the conical intersection, whereas it is damped in the I* channel because ^{3}Q_{0} still has a large bending force constant. The calculated distribution in the ν_{2} umbrella vibrational mode of the CH_{3} product is hot and has a peak at υ = 2 for the I channel, and is cool for the I* channel, in good agreement with recent experiments. This channel selectivity is due to the difference in the preferred structure of the CH_{3} group outside the conical intersection region; while the ^{3}Q_{0} surface prefers a bent CH_{3} until the CH_{3}-I distance becomes very large, ^{1}Q_{1} wants a planar CH_{3}. The location of conical intersection and the ground-excited energy difference there are in good agreement with those deduced from experiment if a dynamical effect is taken into account.

本文言語 | English |
---|---|

ページ（範囲） | 4858-4876 |

ページ数 | 19 |

ジャーナル | The Journal of Chemical Physics |

巻 | 94 |

号 | 7 |

DOI | |

出版ステータス | Published - 1991 |

外部発表 | はい |

## ASJC Scopus subject areas

- 物理学および天文学一般
- 物理化学および理論化学

## フィンガープリント

「Ab initio potential energy surfaces and trajectory studies of A-band photodissociation dynamics: CH_{3}I*→CH

_{3}+ I and CH

_{3}+ I*」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。