MOLECULAR-DYNAMICS STUDIES OF MELTING AND SOLID-STATE TRANSITIONS OF TEF6 CLUSTERS

被引:18
作者
XU, SM [1 ]
BARTELL, LS [1 ]
机构
[1] UNIV MICHIGAN, DEPT CHEM, ANN ARBOR, MI 48109 USA
关键词
D O I
10.1021/j100153a022
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Clusters of TeF6 composed of 100, 128, 150, 250, and 350 molecules were examined by molecular dynamics simulations to analyze structural, energetic, and kinetic aspects of phase changes. Crystalline phases studied included body-centered cubic and four different, particularly compact structures. As had been observed experimentally for large clusters, the bcc phase transformed at an extremely rapid rate, upon fast cooling, to a monoclinic phase unknown in the bulk, for reasons that are now well understood. Melting and solid-state transitions were reproducible when clusters were heated but not when they were cooled, owing to the element of chance in the nucleation step involved. Transitions were spread out over an appreciable range of temperatures and began at the surface when clusters were heated and in the interior when they were cooled. Conventions for defining characteristic transition temperatures were introduced. These transition temperatures decreased approximately linearly with the reciprocal of cluster radius, for the solid-state phase change as well as for melting. All of the above behavior of clusters is in good qualitative but poor quantitative accord with conventional capillary theory based on molecularly sharp interfaces. Limited comparisons are made between simulations including and excluding effects of partial electrostatic charges on the atoms.
引用
收藏
页码:13550 / 13556
页数:7
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