Two-pulse laser control of bond-selective fragmentation

We elaborate on a two-pulse (pump-pump) laser control scheme for selective bond-breaking in molecules [Amstrup and Henriksen, J. Chem. Phys. 97, 8285 (1992)]. We show, in particular, that with this scheme one can overcome the obstacle of intramolecular vibrational relaxation. As an example, we consider an ozone molecule with isotopic substitution, that is, (OOO)-O-16-O-16-O-18. It is shown that asymmetric bond stretching can be created in simple (intense) laser fields. We predict that an alternating high selectivity between the channels O-16+(OO)-O-16-O-18 and (OO)-O-16-O-16+ O-18 can be obtained when such a non-stationary vibrating ozone molecule is photodissociated with short laser pulses (similar to 10-15 fs) with a time delay corresponding to half a vibrational period (similar to 17 fs). (C) 1996 American Institute of Physics.