title: Hot and solid gallium clusters: too small to melt.
abstract: A novel multicollision induced dissociation scheme is employed to determine the energy content for mass-selected gallium cluster ions as a function of their temperature. Measurements were performed for Ga(+)(n) (n=17 39, and 40) over a 90-720 K temperature range. For Ga+39 and Ga+40 a broad maximum in the heat capacity-a signature of a melting transition for a small cluster-occurs at around 550 K. Thus small gallium clusters melt at substantially above the 302.9 K melting point of bulk gallium, in conflict with expectations that they will remain liquid to below 150 K. No melting transition is observed for Ga+17.
authors.affiliation: Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405-7102, USA.
authors.forename: Gary A
authors.initials: GA
authors.lastname: Breaux
authors.forename: Robert C
authors.initials: RC
authors.lastname: Benirschke
authors.forename: Toshiki
authors.initials: T
authors.lastname: Sugai
authors.forename: Brian S
authors.initials: BS
authors.lastname: Kinnear
authors.forename: Martin F
authors.initials: MF
authors.lastname: Jarrold