A QUANTUM-MECHANICAL STUDY OF DISSOCIATIVE HE-2 COLLISIONS(H)

Accurate quantum mechanical. calculations are made for a dissociative He + H-2 collision on a realistic potential energy surface by using th e discrete-variable-representation (DVR) method of Sakimoto and Onda ( J. Chem. Phys. 100 (1994) 1171). The molecular orientation (angle gamm a) relative to the intermolecular (He-H-2) axis is frozen in the calcu lation, and the molecular-orientation dependence of the dissociation i s investigated by changing the angle as gamma = 0 (collinear), pi/4, a nd pi/2 (T-shape). It is found that the dissociation probability is st rongly dependent on the molecular orientation, and the molecule dissoc iates more frequently in the T-shape configuration rather than in the collinear one. Furthermore, the dissociation probabilities are compare d with the results obtained by the standard close coupling (CC) method for the T-shape configuration (Nobusada et al., Chem. Phys. Letters 2 33 (1995) 399). The DVR method can provide accurate dissociation proba bilities even in the case that convergence has not been fully achieved in the previous CC study.