Calculation of disulfide neutral and anion molecular excitation energies

Abstract

The calculation of exited state of molecule require a multireference decription of the wave function. First-order configuration interaction (FOCI) calculations provide such a description but are still feasible for relatively large systems. A test of the method is provided by modeling the spectra of the S-S - bond with the molecules HSS - and CH 3 SS - . The first excitation energy is assigned to a band in the rhodanese enzyme that has been attributed to a S-S - bond at the enzyme active site. The broad absorption spectra of the corresponding neutral molecules can also be understood from the FOCI calculations