1999/11/21 by Ana Proykova, Proykova, Ana, Dessislava Nikolova +3
Physics and Astronomy · #Atomic and Molecular Clusters (physics.atm-clus) #Computational Physics (physics.comp-ph) #FOS: Physical sciences #physics.atm-clus #physics.comp-ph
paper · pdf · doi:10.48550/arxiv.physics/9911049
15 pages, RevTeX
arxiv created 1999/11/21 · arxiv updated 2009/12/01
The dynamic orientational order-disorder transition of clusters consisting of octahedral molecules is formulated in terms of symmetry-adapted rotator functions. The transition from a higher-temperature body-centered-cubic, orientationally disordered phase to a lower-temperature, monoclinic, orientationally-ordered phase is a two-step process. The higher-temperature transition has two local minima in the free energy, like a finite-system counterpart of a first-order transition. Simulations show the lower-temperature transition is continuous. The analytic theory predicts a temperature of 27K for this transition, for a 59-molecule cluster of tellurium hexafluoride in a good agreement with the ~30K result of canonical Monte Carlo calculations.