Theoretical Study on Chemical Reaction Transition State
Grant-in-Aid for Overseas Scientific Survey.
|Allocation Type||Single-year Grants|
|Research Institution||Okazaki National Research Institutes|
MOROKUMA Keiji Okazaki National Research Institutes , Institute for Molecular Science, 分子科学研究所, 教授 (40111083)
DIDIEU Alain Universite Louis Pasteur, パスツール大学・量子化学研究室, 室長
LEFORESTIER Claude Universite de Paris-Sud, 理論化学研究室, 教授
KOGA Nobuaki Okazaki National Research Institutes, Institute for Molecular Science, 分子科学研究所, 助手 (80186650)
YAMASHITA Koichi Institute for Fundamental Chemistry, 主任研究員 (40175659)
|Project Period (FY)
Completed(Fiscal Year 1992)
|Keywords||Complex coordinate method / Discrete variable representation / Resonance scattering states / Transition state spectroscopy / oxo complex / Hydroxylation / Ab initio molecular orbital method / Theoretical chemistry|
We have carried out theoretical studies on the electronic and geometrical structure of a transition state in the two interesting fields : reactions in gas phase and those of transition metal complexes.
The photodetachment experiment by Neumark et al. offers an excellent opportunity for the observation of resonance scattering states in the transition state region of bimolecular chemical reactions. We developed a new method to study the resonance scattering states using the DVR formulation of the complex coordinate method. The resonance positions and widths are determined from the complex eigenvalues of the complex scaled Hamiltonian matrix. The method was applied to the photodetachment spectroscopy of the ClHCl anion. The program code has been developed fro the hyperspherical coordinates system. In the case of ClHl neutral dissociation process, the radial component of the hyperspherical coordinates system nearly corresponds to the reaction path. The LEPS potential energy function was use
d. Along radial coordinate, the surface states (vibrationally adiabatic potential energy curves) show that two wells which can support resonance scattering states have been found at the energy of around 5000 and 7000 cm^-. We applied the complex DVR method to the lower resonance state of the system by rotating the radial coordinates to the complex plane. A resonance state has been located at the resonance position of 5189.8 cm^- and the width of 16.9 cm^<-1>. The results are in good agreement with the ones obtained by a standard L^2 variational method.
The oxidation of hydrocarbons by homogeneous catalyst is a subject of strong current interest. Among the recent advances made in this field, on finds the use of hydroperoxides such as t-BuOOh with group 10 transition metal complexes (Ni, Pd, Pt). According to the experiments by van Koten et al. we studied with ab initio molecular orbital method the model reaction, Pd(CH_3)_2(NH_3)_2+H_2O_2, in order to assess the possible existence of a Pd=O oxo intermediate and if so, to determine its structure, and to check whether other structures resulting from the interaction of ROOH with the Pd(II) complex might be also involved. The reaction leading to Pd(O)(CH_3)_2(NH_3)_2+H_2O was calculated at the correlated MP2 level to be only 2 kacl/mol endothermic, showing that the oxo complex could de an intermediate. Less
Research Output (4results)