Electric dipole polarizability of aluminum phosphide clusters AlnPn (n=2-9) and electron delocalization

We have calculated the static dipole polarizabilities of stoichiometric AlnPn clusters with n=2-9 at HF, B3LYP, B3PW91 and mPW1PW91 levels of theory using basis sets of increasing size. Our results show that AlP clusters behave like the well studied GaAs clusters and their per-atom polarizabilities decrease rapidly with cluster size. At HF and the DFT levels the per-atom-mean polarizability saturates with size after n=4. Finally, from the methodological viewpoint, our results show that for those clusters, the different hybrid density functionals we used converge in the computation of the per-atom-mean polarizability as the size of the cluster increases.