Ab initio three-dimensional quantum dynamics of Ag-3 clusters in the NeNePo process

The first three-dimensional quantum-dynamical ab initio simulation of the l arge amplitude vibrational dynamics of an Ag-3 cluster initiated from its l inear transition state is presented, This can be monitored by femtosecond p ump-probe negative-ion to neutral-to-positive-ion spectroscopy with zero el ectron kinetic energy (NeNePo-ZEKE). The time evolution of the representati ve wavepacket confirms the dynamical effects which have been discovered pre viously by Wigner-type semiclassical simulations: the initial coherent bend ing and stretching from linear to near equilateral triangular configuration , followed by intracluster collision and intracluster vibrational relaxatio n with a weak fractional revival. In addition, the quantum wavepacket shows interferences and spreading. (C) 2000 Elsevier Science B.V.