Three-dimensional global optimization of Nan+ sodium clusters in the range n≤40

Likely candidates for the ionic structure and lowest-energy minima of cationic sodium clusters Na-n(+) are presented in the size range n=4-40. We perform a systematic and unconstrained global optimization by the basin-hopping method with three different energy functions: a many-body empirical classical potential modified to account fur the extra ionic charge, a simple quantal Huckel-type model, and a density-functional-theory-based orbital-free model. The similarities and differences between the models are discussed, and the global shapes are analyzed with the Hill-Wheeler parameters.