A many-body approach to the vibrational structure in molecular electronic spectra. II. Application to nitrogen, carbon monoxide, and formaldehyde

The theory developed in the preceding paper is applied to calculate the vibrational structure in optical absorption and electron impact spectra of N₂ and CO and in the photoelectron spectra of H₂CO and D₂CO. In addition, the vibrational structure of a recently measured shake-up line in the photoelectron spectrum of N₂ is computed. The influence of anharmonicity effects on the Franck-Condon factors is discussed and a very simple scheme to take these effects into account is proposed. The one-particle approximation is shown to provide a fairly accurate picture in most cases. For formaldehyde many-body effects are incorporated into the vibrational coupling constants, leading to an improved agreement with experiment for all bands. The assignment of the third and the fourth ionization potential of formaldehyde, which has been controversial, is clarified.