## 摘要

The potential energy surface (PES) of the CH_{3}OH system has been characterized by ab initio molecular orbital theory calculations at the G2M level of theory. The mechanisms for the decomposition of CH_{3}OH and the related bimolecular reactions, CH_{3}+ OH and ^{1}CH_{2}+ H_{2}O, have been elucidated. The rate constants for these processes have been calculated using variational RRKM theory and compared with available experimental data. The total decomposition rate constants of CH_{3}OH at the high- and low-pressure limits can be represented by k^{∞}= 1.56 × 10^{16} exp(−44310/T) s^{−1} and k_{Ar} ^{0}= 1.60 × 10^{36}T^{−12.2} exp(−48140/T) cm^{3} molecule^{−1} s^{−1}, respectively, covering the temperature range 1000–3000 K, in reasonable agreement with the experimental values. Our results indicate that the product branching ratios are strongly pressure dependent, with the production of CH_{3}+ OH and ^{1}CH_{2}+ H_{2}O dominant under high (P>10^{3} Torr) and low (P<1 atm) pressures, respectively. For the bimolecular reaction of CH_{3} and OH, the total rate constant and the yields of ^{1}CH_{2}+ H_{2}O and H_{2}+ HCOH at lower pressures (P<5 Torr) could be reasonably accounted for by the theory. For the reaction of ^{1}CH_{2} with H_{2}O, both the yield of CH_{3}+ OH and the total rate constant could also be satisfactorily predicted theoretically. The production of ^{3}CH_{2}+ H_{2}O by the singlet to triplet surface crossing, predicted to occur at 4.3 kcal mol^{−1}above the H_{2}C···OH_{2} van der Waals complex (which lies 82.7 kcal mol^{−1} above CH_{3}OH), was neglected in our calculations.

原文 | English |
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頁（從 - 到） | 191-205 |

頁數 | 15 |

期刊 | Faraday Discussions |

卷 | 119 |

發行號 | 1 |

DOIs | |

出版狀態 | Published - 1 1月 2002 |

## 指紋

深入研究「Low-energy paths for the unimolecular decomposition of CH_{3}OH: A G2M/statistical theory study」主題。共同形成了獨特的指紋。