Structures and electronic properties of VSi ( = 14-20) clusters: a combined experimental and density functional theory study.

We present a systematic study of the structures and electronic properties of vanadium-doped silicon cluster anions, VSi ( = 14-20), by combining photoelectron spectroscopy (PES) measurements and density functional theory (DFT) based theoretical calculations. High resolution PES of low temperature (10 K) clusters are acquired at a photon wavelength of 248 nm. Low-lying structures of VSi are obtained by a genetic algorithm based global minimum search code combined with DFT calculations. Excellent agreement is found between the measured PES and the simulated electron density of states of the putative ground-state structures. We conclude that clusters with sizes = 14 and = 15 prefer cage-like structures, with the encapsulated vanadium atom bonding with all silicon atoms, while a fullerene-like motif is more favorable for ≥ 16. For the sizes = 16 to 19, the structures consist of a V@Si with two, three, four, and five Si atoms on the surface of the cage. For = 20 the structure consists of a V@Si with five Si atoms on the surface of the cage. VSi has the highest stability and stands out as a simultaneous closing of electronic and geometrical shells.