Zanchet Alexandre, Bussery-Honvault Beatrice, Honvault Pascal
Laboratoire PALMS, UMR CNRS 6627, Université de Rennes 1, Campus de Beaulieu, 35042 Rennes Cedex, France.
J Phys Chem A. 2006 Nov 2;110(43):12017-25. doi: 10.1021/jp064352p.
The C((3)P) + OH(X (2)Pi) --> CO(X (1)Sigma(g)(+)) + H((2)S) reaction has been investigated by ab initio electronic structure calculations of the X(2)A' state based on the multireference (MR) internally contracted single and double configuration interaction (SDCI) method plus Davidson correction (+Q) using Dunning aug-cc-pVQZ basis sets. In particular, the multireference space is taken to be a complete active space (CAS). Improvement over previously proposed potential energy surfaces for HCO/COH is obtained in the sense that present surface describes also the potential part where the CO interatomic distance is large. A large number of geometries (around 2000) have been calculated and analytically fitted using the reproducing kernel Hilbert space (RKHS) method of Ho and Rabitz both for the two-body and three-body terms following the many-body decomposition of the total electronic energies. Results show that the global reaction is highly exothermic ( approximately 6.4 eV) and barrierless (relative to the reactant channel), while five potential barriers are located on this surface. The three minima and five saddle points observed are characterized and found to be in good agreement with previous work. The three minima correspond to the formation of HCO and COH complexes and to the CO + H products, with the COH complex being a metastable minimum relative to the product channel. The five saddle points correspond to potential barriers for both the dissociation/formation of HCO and COH into/from CO + H, to barriers for the isomerization of HCO into COH and to barriers for the inversion of HCO and COH through their respective linear configuration.
通过基于多参考（MR）内收缩单双组态相互作用（SDCI）方法并加上戴维森校正（+Q），使用邓宁aug-cc-pVQZ基组对X(2)A'态进行从头算电子结构计算，研究了C((3)P) + OH(X (2)Pi) --> CO(X (1)Sigma(g)(+)) + H((2)S)反应。特别是，多参考空间被视为一个完全活性空间（CAS）。相对于先前提出的HCO/COH势能面有了改进，因为当前的势能面也描述了CO原子间距离较大时的势能部分。已经计算了大量几何构型（约2000个），并使用Ho和Rabitz的再生核希尔伯特空间（RKHS）方法对总电子能量进行多体分解后的两体和三体项进行了分析拟合。结果表明，全局反应是高度放热的（约6.4 eV）且无势垒（相对于反应物通道），而在这个势能面上有五个势垒。观察到的三个极小值和五个鞍点得到了表征，并且发现与先前的工作吻合良好。这三个极小值分别对应于HCO和COH络合物的形成以及CO + H产物的形成，其中COH络合物相对于产物通道是一个亚稳极小值。这五个鞍点分别对应于HCO和COH分解/形成CO + H的势垒、HCO异构化为COH的势垒以及HCO和COH通过各自线性构型反转的势垒。
