The structures, conversions and fragmentations of C2H6O2+ isomers:: An ab initio study

The fragmentations of a C2H6O dication in both singlet and triplet states are investigated in the present study. We propose several probable reaction channels to explain the source of the peaks which are found in the mass spectrum of ethanol under an intense laser field, but fail to reproduce it theoretically by considering only the fragmentation of a C2H6O radical cation. It is difficult for the C2H6O2+ isomers in singlet state to undergo fragmentation, except for the H-2 elimination from ethanol dication, to generate CH3COH2+. However, the fragmentation can take place easily from the C2H6O2+ isomers in triplet state. There exist low energy channels of the C2H6O dication in singlet state, to generate CH3COH2+, CH4+, CHOH+, CH3+, CHOH2+, CH2+, (CHOH2+)-O-2 COH+, H+, CH2CHOH2+, CH2CH+ and H3O+. However, with similar consideration, the low energy channels of OH+, (CHCH2+)-C-3(T), (CHCH2+)-C-2, (HO+)-O-2, CH2O+ and CH2OH2+, are available only in triplet state. The inter-conversions between any two C2H6O2+ isomers in both singlet and triplet states are easier than their fragmentation reactions, except for CH2+ and beta-H eliminations from those dications in triplet state. (c) 2006 Elsevier B.V. All rights reserved.