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

Abstract 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 CH 3 OH with an energetic electron beam. Two observed metastable fragmentation reactions were studied: decay of the molecular parent ion CH 3 OH + into CHOH + and neutral 2H, and decay of the fragment ion CH 3 + into CH 2 + 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 CH 2 + ions, respectively. We suggest a metastable electronically-excited state as a reason for the CH 3 + fragmentation reactions.