MOLECULAR VIBRATIONAL-STATE DISTRIBUTIONS IN COLLISIONS

Experimental vibrational spectra of H-2 in the collision with a proton at 30 eV in the laboratory frame are compared to results from calcula tions using the electron nuclear dynamics. Nuclei are treated classica lly. Interpreting the classical vibration in terms of a coherent state yields quantum vibrational levels reproducing the experimental result s. This result indicates that collision dynamics, including vibrationa l excitation, does not require numerical-grid wave packet dynamics for an understanding of the fundamental mechanisms involved, but that the concept of coherent state can provide a simple and accurate method to resolve product vibrational states from fully dynamical classical tra jectories.