Ab initio molecular dynamics simulations modeling low energy collisions of sodium atom with
a cluster with more than thirty water molecules are presented. We follow the dynamics of the atomcluster
interaction and the delocalization of the valence electron of sodium together with changes in the
electron binding energy. This electron tends to be shared by the nascent sodium cation and the water
cluster. IR spectra of the sodium-water cluster are obtained both computationally and experimentally,
with good agreement between the two approaches.