Neutralization-reionization of CH4+•: At which stage does fragmentation occur?

Abstract Experimental (collision-induced dissociative ionization (CIDI) and neutralization-reionization mass spectrometry (NRMS)) and theoretical (ab initio molecular orbital) procedures were used to examine the origin of the fragmentation observed in NRMS experiments on the methane radical cation. Both theory and experiment indicate that in NRMS experiments involving neutralization by species of high ionization energy (e.g. Hg or Xe), the fragmentation occurs largely at the reionization rather than the neutralization stage. The reverse is true for the strongly exothermic neutralization with Na. Corresponding experiments [C 2 H 6 ] +• ions showed similar behaviour.