title: Reactions of liquid and solid aluminum clusters with N2: the role of structure and phase in Al114 (+), Al115 (+), and Al117 (+).
abstract: Kinetic energy thresholds have been measured for the chemisorption of N2 onto Al114 (+), Al115 (+), and Al117 (+) as a function of the cluster's initial temperature, from around 200 K up to around 900 K. For all three clusters there is a sharp drop in the kinetic energy threshold of 0.5-0.6 eV at around 450 K, that is correlated with the structural transition identified in heat capacity measurements. The decrease in the thresholds corresponds to an increase in the reaction rate constant, k(T) at 450 K, of around 10(6)-fold. No significant change in the thresholds occurs when the clusters melt at around 600 K. This contrasts with behavior previously reported for smaller clusters where a substantial drop in the kinetic energy thresholds is correlated with the melting transition.
authors.affiliation: Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, USA.
authors.forename: Baopeng
authors.initials: B
authors.lastname: Cao
authors.affiliation: Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, USA.
authors.forename: Anne K
authors.initials: AK
authors.lastname: Starace
authors.affiliation: Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, USA.
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Judd
authors.affiliation: Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, USA.
authors.forename: Indrani
authors.initials: I
authors.lastname: Bhattacharyya
authors.affiliation: Chemistry Department, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47401, USA.
authors.forename: Martin F
authors.initials: MF
authors.lastname: Jarrold