Predissociation dynamics of the B state of CH_3I by femtosecond pump-probe technique

Abstract

The laser induced predissociation dynamics of the B Rydberg state of CH(3)I following two-photon absorption of a pump pulse was studied with femtosecond pump-probe photoelectron imaging coupled with time-resolved mass spectroscopy. The predissociation lifetime was measured to be 1.55 ps induced by the crossing between the B state and the repulsive A-band. Two possible predissociation channels were observed originating from (a) direct coupling between the B state and the repulsive (3)Q(0) state and (b) a second crossing between the (3)Q(0) and (1)Q(1) states after the coupling between the B and (3)Q(0) states, respectively.