Simulation of photoelectron spectra with anharmonicity fully included: application to the X2A2 <- X1A1 band of furan

Abstract

Using a new unconventional procedure for calculating Franck-Condon factors with anharmonicity fully included the band in the photoelectron spectrum of furan (and deuterated furan) was simulated at the second-order perturbation theory level. All 21 vibrational modes were considered but, in the end, only 4 are required to accurately reproduce the spectrum. Except for our own recent work on ethylene such calculations have been previously limited to tri- or tetra-atomic molecules. Most of the effect of anharmonicity is accounted for in first-order, although second-order corrections to the vibrational frequencies are important. Based on these simulations we were able to improve upon and extend previous assignments as well as suggest further measurements