Date Published:

SEP 25

Abstract:

The role of different electronic states in cage-exit of F atoms for F-2 photodissociation in solid Ar is investigated by nonadiabatic molecular dynamics simulations, using Tully's ``Surface-Hopping'' approach. The 36 potential surfaces involved are treated by the diatomics-in-molecules (DIM) method. A simulation of 255 Ar atoms in an FCC structure with periodic boundary conditions is used. The results are: (I) Direct cage-exit events are not observed. At least two collisions of the F atoms with the Ar cage are necessary for cage-exit. (II) The total singlet to triplet population ratio at the instant of cage-exit is approximately the statistical one. (III) Some cage-exit events occur for the attractive states (1)Sigma(+)(g), (3)pi(u) but their role is much smaller than for the caged species. (IV) The Lambda quantum number distribution at cage-exit is more uniform than for the caged species. Thus, the electronic state distribution for cage-exit differs greatly from that of the caged species. (c) 2007 Elsevier B.V. All rights reserved.