Ejection dynamics of hydrogen molecular ions from methanol in intense laser fields

The ejection of hydrogen molecular ions from two-body Coulomb explosion processes of methanol (CH3OH, CD3OH and CH3OD) in an intense laser field (800 nm, 60 fs, 0.2 PW cm(-2)) is investigated by a coincidence momentum imaging method. From the coincidence momentum maps, the ejection processes of hydrogen molecular ions, CH3OH2+. H-m(+) + CH(3-m) OH+ (m = 2, 3), CD3OH2+ -> D-m(+) + CH(3-m)OH+ (m = 2,3) and CH3OD2+. H-m(+) + CH(3-m) OD+(m = 2, 3), are identified. Based on the results obtained with isotopically substituted methanol, the isotope effect on the ejection process of hydrogen molecular ions is discussed. Furthermore, the ejection of H/D exchanged hydrogen molecular ions (HD+, HD2+ and H2D+) is identified, and the timescales for the H/D exchanging processes are estimated from the extent of anisotropy in the ejection directions.