H＋CO_2→CO＋OH的反应机理和反应速率常数的理论研究

A THEORETICAL STUDY ON THE MECHANISM AND RATE CONSTANTS OF THE REACTION H+CO_2→CO+OH

用从头算方法在ＵＨＦ／３－２１Ｇ水平上研究了Ｈ＋ＣＯ２_ＣＯ＋ＯＨ的反应机理，指出该反应分为３个基元过程进行，第一步为速控步骤。同时用Ｆｕｋｕｉ的内禀反应坐标理论计算了ＩＲＣ，证实了上述反应机理。用传统过渡态理论和变分过渡态理论及相关的隧道效应校正计算了反应的速率常数。

The mechanism of the reaction H+CO2→CO+OH was studied and the transition states and intermediates were optimized by using ab initio method at the UHF/3-21G level of theory. This reaction consists of three elementary processes, and the first one is the rate-controlling step.The intrinsic reaction coordiate(TRC)for each elementary processwas traced by Fukui's ,IRC theory and confimed the reaction mechanism.The theoretical rate constants in the conventional transition state theory and the variational transition state theory with correction of tunneling effect were calculated.