Wave packet bifurcation in ultrafast hydrogen migration in CH3OH+ by pump-probe coincidence momentum imaging with few-cycle laser pulses

Abstract Ultrafast nuclear dynamics in CH 3 OH + has been studied based on the released kinetic energy distributions of the fragment ions in the non-migration (CH 3 OH 2+  → CH 3 +  + OH + ) and migration (CH 3 OH 2+  → CH 2 +  + OH 2 + ) pathways obtained by pump-probe coincidence momentum imaging with few-cycle laser pulses (6.0(5) fs, 2.1(2) × 10 14  W/cm 2 ). A characteristic oscillatory structure with a bifurcation at ∼150 fs in the kinetic energy distribution of the migration pathway is interpreted as the motion of a vibrational wave packet on a bound well around the migrated geometry, oscillating first along the C O bond and bifurcating into bound and dissociating components.