Coincidence momentum imaging of ejection of hydrogen molecular ions from methanol in intense laser fields

Two-body Coulomb explosion processes of methanol (CH3OH) in an intense laser field (0.2 PW/cm2, 60 fs) are investigated by the coincidence momentum imaging method. In the coincidence momentum images, the hydrogen ejection processes, CH3OH2+→Hm++CH(3-m)OH+(m=1-3), are securely identified. From the anisotropy in the angular distributions of the fragment ions, the lifetimes of the corresponding precursor ions CH3OH2+ are estimated to be 70-290 fs for the H+ ejection, 110-550 fs for the H2+ ejection, and much longer than 1.4 ps for the H3+ ejection.