High resolution threshold photoelectron spectrum and autoionization processes of S2 up to 15.0 eV

Abstract

VUV photoionization dynamics of the S2 molecule were re-investigated from threshold up to 15.0 eV, using synchrotron radiation coupled with double imaging photoelectron/photoion coincidence featuring high resolution capabilities. We measured the first threshold photoelectron spectrum of S2 achieving higher resolution than previous literature to derive accurate spectroscopic constants for a few electronic states of the cation including the X2ΠΩ,g ground state and the a4Πu, b4Σg–, and B2Σg– states. We also recorded the total ion yield for S2 up to a photon energy of 15.0 eV which, combined with the threshold photoelectron spectrum, led to the assignment of various autoionizing Rydberg series.