Theoretical investigation on the N+SF2→NS+ reaction involving resonance-enhanced multiphoton ionization process

Abstract

NS + was detected from ionization of the final product of the N(2D)+SF2 reaction by laser multiphoton ionization. NS is not the spectral carrier of our REMPI (resonance-enhanced multiphoton ionization) spectrum. For understanding the experimental facts and to obtain a complete description of the whole process, quantum-chemical calculations were performed. The density functional theory/Becke’s three-parameter hybrid-function calculations indicate that NSF is the product of the most favorable channel of the N+SF2 reaction. The complete active space self-consistent field (CASSCF) potential energy curve calculations predict that 1 1A″ is a predissociative state of NSF with the NS radical and F atom as the dissociation products. The CASSCF vibrational frequencies calculated at the 1 1A″ minimum are in line with the excitation spectrum. The CASPT2 adiabatic excitation energy value of 3.32 eV for the 1 1A″ state is close to the energy value (3.44 eV) of one photon. On the basis of theoretical calculations, it is concluded that NS+ detected in the experiments is produced by one-photon dissociation and ionization of the 1 1A″ excited state of NSF, which is the product of the most favorable channel of the N+SF2 reaction.