title: A limit of stability in supercooled liquid clusters.
abstract: We examine the metastable liquid phase of a supercooled gold nanocluster by studying the free energy landscape using the largest solidlike embryo as an order parameter. Just below freezing, the free energy exhibits a local minimum at small embryo sizes and a maximum at a larger critical embryo size. At T=660 K the free energy becomes a monotonically decreasing function of the order parameter as the liquid phase becomes unstable, indicating that we have reached a limit of stability. In contrast to the mean-field theory predictions for a spinodal, the size of the critical embryo remains finite as the limit of stability is approached. We also calculate the rate of nucleation, independently from our free energy calculations, and observe a rapid increase in its temperature dependence when the free energy barrier is on the order of kT. We suggest that this supports the idea that freezing becomes a barrierless process at low temperatures.
authors.affiliation: Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9, Canada.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Mendez-Villuendas
authors.forename: Ivan
authors.initials: I
authors.lastname: Saika-Voivod
authors.forename: Richard K
authors.initials: RK
authors.lastname: Bowles