Fragmentation and kinetic energy release distribution of ions produced from methanol CH3OH

A double focusing mass spectrometer of reversed Nier-Johnson geometry was used in a research of ionization and fragmentation processes induced by the collision of methanol molecules CH3OH with an energetic electron beam. Two observed metastable fragmentation reactions were studied: decay of the molecular parent ion CH3OH+ into CHOH+ and neutral 2H, and decay of the fragment ion CH3+ into CH2+ and neutral hydrogen. For these reactions the mean values of the kinetic energy release were calculated using MIKE (Mass-Analyzed Ion Kinetic Energy) technique and the KERD (Kinetic Energy Release Distribution) were determined. We obtain the < Ɛ > values of 16 meV and 52 meV for CHOH+ and CH2+ ions, respectively. We suggest a metastable electronically-excited state as a reason for the CH3+ fragmentation reactions.