THE STERIC EFFECT IN A FULL DIMENSIONAL QUANTUM DYNAMICS SIMULATION FOR THE DISSOCIATIVE ADSORPTION OF H-2 ON CU(111)

The rotational alignment of the dissociative adsorption of Hz on the C u(lll) surface has been studied by a six-dimensional quantum dynamics simulation. The theoretical rotational alignment is in excellent agree ment with the experimental measurement of Hou et al. [Science 277, 80 (1997)]. The translational energy threshold of the dissociation is fou nd to increase with increase of rotational quantum number j then to de crease after j = 4 or 5. No substantial difference in the dependence o f rotational alignment on the excess translational energy has been fou nd between the dissociation of H-2 and D-2 on the Cu(lll) surface. The variation of rotational alignment as a function of excess translation al energy is almost independent of the rovibrational level (v,j) of th e initial state. The theoretical study further predicts that the rotat ional alignment curve (a function of translational energy) would first shift toward high translational energy with increasing j, then shift back toward low translational energy after j=5. (C) 1998 American Inst itute of Physics.