Electron propagator theory of the photoelectron spectrum of methanesulfenic acid

Assignment of the photoelectron spectrum of methanesulfenic acid, H3CSOH, i s facilitated by ab initio electron propagator calculations. Close agreemen t exists between experimental peak positions and predictions at the NR2 lev el of theory for the first three ionization energies. A fourth state, which may be obscured by impurities generated in the thermolytic synthesis of ev anescent H3CSOH molecules, is predicted. A nearby correlation state has als o been discovered. Two higher ionization energies predicted by NR2 theory a re in close agreement with a feature identified in the spectrum. Finally, a previously unassigned peak at higher energy has been explained on the basi s of-the NR2 calculations. Dyson orbitals corresponding to each ionization energy are analyzed in terms of their uncorrelated, Hartree-Fock counterpar ts and their atomic constituents.