FREE NUCLEAR DENSITY PROPAGATION IN 2 DIMENSIONS - THE COUPLED-CHANNEL DENSITY-MATRIX METHOD AND ITS APPLICATION TO INELASTIC MOLECULE-SURFACE SCATTERING

A new tool for solving nuclear Liouville-von Neumann equations for unb ound problems in multi-dimensions, termed the Coupled Channel Density Matrix (CCDM) method, is introduced. In this method, applicable to sit uations where a subset of the active modes is ''free'' and another one ''bound'', a mixed representation (coordinate space representation fo r the free, state representation for the bound degrees of freedom) is used for all operators, leading to a set of coupled low-dimensional Li ouville-von Neumann equations. Various numerical investigations are ca rried out to characterize the performance of the method in its applica tion to the non-dissipative inelastic scattering of H-2 molecules and isotopomers from a Cu model surface. (C) 1997 Published by Elsevier Sc ience B.V.