Laser driven ground state photodissociation of HCo(CO)(4): An ab initio quantum molecular dynamics approach

The competition between laser selective dissociation of the axial Co-CO bon d and intramolecular energy redistribution in HCo(CO)(4) is investigated. O ur approach is based on an ab initio calculation of the Cartesian reaction surface Hamiltonian along the Co-CO bond distance using density functional theory. The substrate degrees of freedom are treated within the harmonic ap proximation. We find only two modes which are strongly coupled to the disso ciation reaction, one which can be approximately described as an H-Co stret ching vibration while the second one is an umbrella type vibration of the e quatorial carbonyls. The region of validity for harmonic motion of the subs trate normal modes is explored. (C) 2000 American Institute of Physics. [S0 021-9606(00)01001-1].