Abstract: | By a wavepacket propagation, we demonstrate the possibility of controlling the photodissociation branching ratio between two fragment channels by a single ultrashort linearly chirped laser pulse. It is found that a negatively chirped pulse of a moderate chirp rate completely prohibits the production of one of the photofragment channels. Two characteristics of chirped laser pulses contribute to this remarkable effect: the mechanism of adiabatic rapid passage (ARP) for the population transfer between the ground and excited states and the intrapulse pump‐dump process for determining the branching ratio. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 72: 525–532, 1999 |