Theoretical study of open-shell van der Waals complexes

Abstract

The present thesis is devoted to a theoretical study of van der Waals open-shell atom-diatom and diatom-diatom complexes occurring in the entrance channels of the hydrogen transfer chemical reactions. The study of the Cl-HF and Br-HCN systems can be split into two main parts. The first part concerns ab initio electronic structure calculations for potential energy surfaces and the analytic fit of these potentials. The second part consists of dynamics (bound state) calculations with the fitted potentials. For OH-HCl a dynamics study has been carried out using potential energy surfaces obtained earlier by another authors. For the Cl-HF and Br-HCN systems we have employed various dynamical models (1D, 2+1D, and 3D), for OH-HCl we have used 3+1D and 4D models; all of these are explained and compared in the corresponding chapters. From the dynamics calculations we have derived spectroscopic parameters, such as bend and stretch frequencies, red shifts, and Renner-Teller effects. The theoretical data were compared with available experimental results and found to agree well.