Franck–Condon profiles in photodetachment-photoelectron spectra of and based on vibrational configuration interaction wavefunctions

Abstract

Explicitly electron correlating coupled cluster calculations, CCSD(T)-F12a, were performed to determine three-dimensional potential energy hypersurfaces of disulphanide and disulphanyl in an automated approach. Surfaces for different electronic states were used in a Watson rovibrational Hamiltonian ansatz to obtain the correlated anharmonic vibrational wavefunctions. Subsequently the anharmonic Franck–Condon overlap integrals were evaluated. The computed Franck–Condon profiles were compared to experimental photodetachment-photoelectron spectra and confirm essentially the assignments made previously. The profiles indicate, however, additional weaker, and as of yet unresolved, additional features.

Keywords:

• Franck–Condon
• VSCF/VCI
• photodetachment-photoelectron spectra
• CCSD(T)-F12
• HS₂

Acknowledgements

RB acknowledges the Volkswagen Foundation for financial support and the Center for Scientific Computing (CSC) Frankfurt for computer time. This work has been supported by the Deutsche Forschungsgemeinschaft (Grant Ra 656/11-1).