Theoretical study on the structure and energetics of alkali halide clusters

The structures of alkali halide clusters Na_nF_n, Li_nF_n and Na_nCl_n, and their metal-excess clusters Na_nF_n−1⁺, Li_nF_n−1⁺ and Na_nCl_n−1⁺ were investigated by the ab initio molecular orbital method for cluster sizes from 1 to 14. The magic numbers for the neutral clusters Na_nF_n, Li_nF_n and Na_nCl_n are 4, 6, and 8. The most stable structure for these cluster sizes is a perfect crystallite for Na_nF_n and Na_nCl_n, and a double ring for Li_nF_n. The magic numbers for the metal-excess clusters are 5 and 8, which are near ideal cuboids with (100) facets.