Geometrically induced melting variation in gallium clusters from first principles

First-principles Born-Oppenheimer molecular dynamics simulations of gallium clusters reproduce experimental specific heats to a high degree of accuracy, with no experimental input or fitting. Remaining systematic shifts of the melting temperature highlight important limitations of density-functional approximations. An analysis of the structural changes observed as a function of finite temperature provides evidence for the assignment of a melting temperature to a specific peak in the specific heat. The structural basis for features in the specific heat curves, in particular, the existence of multiple peaks, is demonstrated.