Franck-Condon simulation of the photoelectron spectrum of SO2- including Duschinsky effects

A theoretical method to calculate multidimensional Franck-Condon factors including Duschinsky effects is described and used to simulate the photoelectron spectrum of the anion SO2-. Geometry optimizations and harmonic vibrational frequency calculations have been performed on the X˜1A1 state of SO2 and X˜2B1 state of SO2-. Franck-Condon analyses and spectral simulation were carried out on the first photoelectron band of SO2-. The theoretical spectra obtained by employing CCSD(T)/6-311+G(2d,p) values are in excellent agreement with the experiment. In addition, the equilibrium geometric parameters, re(OS) = 0.1508 ± 0.0005 nm and θe(O-S-O) = 113.5 ± 0.5°, of the X˜2B1 state of SO2-, are derived by employing an iterative Franck-Condon analysis procedure in the spectral simulation.