Channel-specific photoelectron angular distribution in laboratory and molecular frames for dissociative ionization of methanol in intense ultraviolet laser fields

We investigate dissociative ionization of CH3OH in an intense laser field (398 nm, 76 fs, 8.9×1012 W/cm2) by photoelectron-photoion coincidence momentum imaging. It is revealed from the analysis of the channel-specific photoelectron angular distributions that CH3OH is decomposed into CH2OH+ + H after the four-photon ionization to the vibrationally highly excited states of the electronic ground state of CH3OH+ and into CH3+ + OH after the five-photon ionization to the second electronically excited state of CH3OH+, and that these two channels are also opened after CH3OH+, prepared by the four-photon ionization, is photoexcited further into the electronically excited states