VIBRATIONALLY RESOLVED SPECTRA FROM SHORT-TIME QUANTUM MOLECULAR-DYNAMICS BY THE FILTER-DIAGONALIZATION METHOD

The possibility of calculating vibrationally resolved spectra from sho rt numerically exact and approximate quantum dynamical propagations us ing the new filter-diagonalization method is explored. The benchmark p rocess under study concerns electron photodetachment in the I-Ar2 comp lex. Comparison with results obtained from long-time propagations and with experiment reveals the power of the filter-diagonalization scheme . Using the new methodology it now becomes possible to extract positio ns of spectral peaks for large polyatomic systems from approximate qua ntum propagations e.g., by means of the recently developed classical s eparable potential approach. (C) 1997 Elsevier Science B.V.