A rapid method for determining excited state surface parameters and bond length in diatomic molecules and calculating wavefunctions for Franck-Condon factors using the quantum momentum method

Abstract

A fast and simple method for determining molecular potential energy parameters for excited dectronic states is presented. This method uses the moments of the observed vibronic spectra. It is particularly accurate in determining equilibrium bond lengths and is a good substitute for an iterative, least-squares Franck-Condon analysis. The calculation of wavefunctions for Franck-Condon factors Using the quantum momentum method is also reported. This method is not limited to low vibrational numbers and does not have problems with overflow and insufficient precision that are associated with methods using analytic forms of the Morse potential wavefunction. A program incorporating both the spectral moment method and the quantum momentum method is described. It provides a package for evaluating excited state molecular potential parameters and for simulating electronic-vibrational spectra for one vibrational mode at a time. © 1991.