Competition between planar and nonplanar structure in alkali hexamers: The example ofLi6

Abstract
The optical-absorption spectrum of Li6 has been observed by depletion spectroscopy in the 400–700-nm range. The experimetnal results are compared with theoretical spectra calculated for the three Li6 structures in competition and we have been able to unambiguously determine the most stable Li6 geometry as being the C2v tripyramidal geometry.