Jm. Thompson et A. Bulgac, TEMPERATURE-DEPENDENCE OF THE SINGLE-PARTICLE SPECTRUM IN SODIUM CLUSTERS, Zeitschrift fur Physik. D, Atoms, molecules and clusters, 40(1-4), 1997, pp. 462-465
We show that the electronic density of states of small sodium clusters
is strongly affected by both thermal fluctuations about the ground st
ate ionic configuration and transitions between different shape isomer
s as the temperature of the cluster is increased. Contrary to common e
xpectations, the clusters undergo a sharp transition in the temperatur
e range of 100K to 150K, after which the single-particle level distrib
utions become bimodal. At even higher temperatures the signature of th
e ground state configuration disappears, and the density of states is
dominated by higher energy isomers. We also discuss the implications o
f these findings for the interpretation of the photoelectron spectra o
f these systems.