Structure and properties of ionized and neutral condensed clusters of Si, Ge, Sn and Pb.

The relative abundances of medium-size clusters X sub n sup (+, -,0) of X = Si, GE, Sn or Pb, with 7 = n = 30, as prepared in various ways after vapor-phase condensation, are determined by enthalpic, entropic and dynamic factors. Valence electronic structure determines chemical trends in (magic number) peaks in these relative abundances. Theoretical models of the valence structure explain these trends in detail. New cylindrical structures are identified at n = 15, 18 and 21 for X - over n with X = Si and Ge. General trends in ionization potentials and electron affinities are discussed.