Molecular Physics seminar

Electronic spectra from sophisticated model Hamiltonians based on coupled-cluster calculations

by Prof. John Stanton (University of Texas at Austin)

FA32 ()


This talk reviews some recent advances in the computation of molecular electronic spectra. Specifically, the work focuses on "difficult" systems in which the usual Franck-Condon model is inadequate because of the coupling between nuclear and electronic degrees of freedom. The approaches used are based on fairly elaborate parametrizations of the diabatic model Hamiltonian method that was popularized by Köppel, Domcke and Cederbaum (KDC) many years ago. The parametrizations are based on high-level electronic structure calculations using equation-of-motion coupled-cluster theory, including a recent ansatz that provides a well-defined description of the (quasi)diabatic electronic states that form the basis in the model Hamiltonian. The talk begins with a very simple introduction to vibronic effects in molecular spectroscopy, provides an overview of the KDC Hamiltonian and the parametrization approach, and concludes with examples from photodetachment and absorption spectroscopy.