Electric dipole polarizabilities of isolated gallium arsenide clusters

The static electric dipole polarizabilities of isolated GaN AsM clusters withN + M = 4–30 atoms and approximatly 1:1 composition have been measured in dependence of the cluster size N + M by means of a molecular beam deflection technique. A striking size-dependent behaviour has been observed for small GaNAsM clusters with up to 15 atoms. Within this size range the polarizability oscillates strongly between low values for even and high values for odd numbers of atoms N + M. For clusters with N + M < 12 the polarizability of gallium rich clusters is significantly larger than the values obtained for arsenic rich clusters whereas the opposite effect was observed for larger clusters with N + M >12.