A molecular dynamics study of structural transitions in small water clusters in the presence of an external electric field Clusters of octahedral molecules mimicking TeF 6 afford a vehicle to investigate the analog in small clusters of structural phase transitions through molecular dynamics simulations. Three phaselike forms occur for the solid clusters, both closed-shell structures of 51, 89, and 137 molecules, and open-shell structures of 50, 81, and 129 molecules. The indications are that the free energy has at least two minima as a function of the order parameter. However, whether these converge to a single minimum as N, the number of molecules in the cluster, grows large, leading to a second-order transition in the bulk, or remain apart, implying at least a weak first-order transition in the bulk limit, cannot be determined from the simulations.

No abstract

Ground state of the quantum anisotropic planar rotor model: A finite size scaling study of the orientational order-disorder phase transition

The thermodynamic properties of (T eF6)59 clusters that undergo temperature-driven phase transitions have been calculated with a canonical J-walking Monte Carlo technique. A parallel code for simulations has been developed and optimized on SUN3500 and CRAY-T3E computers. The Lindemann criterion shows that the clusters transform from liquid to solid and then from one solid structure to another in the temperature region 60-130 K.