A quantum mechanical investigation is made for the collision induced d
issociation (CID) process, He + Na-2 --> He + Na + Na, by treating the
vibrational and rotational degrees of freedom in fully decoupled appr
oximation. The collision problem to be solved is simply reduced to the
calculation of the scattering phase shift that depends parametrically
on the molecular orientation and on the inter nuclear distance of the
molecule. The present method gives a useful approach to study vibrati
onal energy transfer and dissociation in collisions of heavy (or polya
tomic) molecules which lie in any vibrational states. (C) 1998 Elsevie
r Science B.V.