CONTROL OF HOD PHOTODISSOCIATION DYNAMICS VIA BOND-SELECTIVE INFRARED MULTIPHOTON EXCITATION AND A FEMTOSECOND ULTRAVIOLET-LASER PULSE

A scheme for controlling the outcome of a photodissociation process is studied. It involves two lasers-one intense laser in the infrared region which is supposed to excite a particular bond in the electronic ground state, and a second short laser pulse in the ultraviolet region which, at the right moment, excites the molecule to a dissociative electronic state. We consider the HOD molecule which is ideal due to the local mode structure of the vibrational states. It is shown that selective and localized bond stretching can be created in simple laser fields. When such a nonstationary vibrating HOD molecule is photodissociated with a short laser pulse (approximately 5 fs) complete selectivity between the channels H + OD and D + OH is observed over the entire absorption band covering these channels.