Static dipole polarizability of small mixed sodium-lithium clusters

We have measured the static dipole polarizability of Nay-xLix clusters (wit h y=2, 3, 4, and 8) by molecular beam deflection technique. For a given siz e, the polarizability of pure lithium clusters is smaller than the polariza bility of pure sodium clusters. For mixed clusters, a smooth decrease in th e polarizability is observed as the proportion of lithium atoms increases. For the NaLi molecule, both experimental permanent dipole and average polar izability have been obtained. Experimental results are compared to results of density functional theory and configuration interaction single and doubl e (CISD) ab initio calculations. (C) 1999 American Institute of Physics. [S 0021-9606(99)01512-3].