Multiphoton dissociation/ionisation of dimethyl sulfide

Multiphoton dissociation/ionisation studies have been carried out at 335 nm for dimethyl disulfide (CH3SSCH3) using a time-of-flight-mass spectrometer . The prominent ion signals observed are CH3+ S+, HCS+ and S-2(+). No evide nce for the formation of a parent ion signal was observed. The laser power variation experiments show a two-photon dependence for the most prominent H CS+ ion. The presence of a signal at m/e 30 is explained in terms of concer ted elimination of ethane from the excited neutral CH3SSCH3 via a cyclic tr ansition state. It is inferred that the multiphoton dissociation of CH3SSCH 3 at 355 mn involves both S-S and C-S bond cleavage. Based on these results , it has been suggested that CH3S+ isomerises to CH2SH+, which undergoes un imolecular decay to produce HCS+ by H-2 elimination. The results have been interpreted in terms of the dissociation of the parent molecule using two p hotons, followed by the ionisation of the fragments. Copyright (C) 2001 Joh n Wiley & Sons, Ltd.