  Unimolecular evaporation in rotating, non-spherical atomic clusters is
investigated using Phase Space Theory in its orbiting transition state version.
The distributions of the total kinetic energy release epsilon_tr and the
rotational angular momentum J_r are calculated for oblate top and prolate top
main products with an arbitrary degree of deformation. The orientation of the
angular momentum of the product cluster with respect to the cluster symmetry
axis has also been obtained. This statistical approach is tested in the case of
the small 8-atom Lennard-Jones cluster, for which comparison with extensive
molecular dynamics simulations is presented. The role of the cluster shape has
been systematically studied for larger, model clusters in the harmonic
approximation for the vibrational densities of states. We find that the type of
deformation (prolate vs. oblate) plays little role on the distributions and
averages of epsilon_tr and J_r except at low initial angular momentum. However,
alignment effects between the product angular momentum and the symmetry axis
are found to be significant, and maximum at some degree of oblateness. The
effects of deformation on the rotational cooling and heating effects are also
illustrated.
