A DFT study on the heredity-induced coalescence of icosahedral basic clusters in the rapid solidification
YQ Jiang and P Peng and DD Wen and SC Han and ZY Hou, COMPUTATIONAL MATERIALS SCIENCE, 99, 156-163 (2015).
A density-function-theory (DFT) calculation conjoining with molecular dynamics (MD) simulation is performed to investigate the structural stability and formation capability of extended icosahedral Agn (n = 19, 23, 24, 25) clusters linked by vertex-shared (VS), edge-shared (ES), face-shared (FS) and inter-cross-shared (IS) atoms in the rapid solidification. The chemical hardness g as a measure of chemical stability has been adopted to characterize and assess the structural stability and configuration hereditary ability of these extended icosahedral clusters, and their heats of formation DHR-P in the bi- cluster association mode of Ag-13 + Ag-m -> Ag-n (n = 19, 23, 24, 25, m = n - 13) is also calculated by a transition state (TS) search method on the basis of linear synchronous transit (LST) and quadratic synchronous transit (QST) technique. It is found that the high structural stability of inheritable Ih-Ag-13 icosahedral short-range orders (ISROs) and IS- linkages related to icosahedral medium-range orders (IMROs) can be attributed to their large chemical hardness g relative to FS-, ES- and VS-linkages, and to some extent a large released calorie DHR-P in the formation of D-5h-Ag-19 clusters should be responsible for the coalescence preference of IS-linkages in super-cooled liquids and subsequent intensive emergence in rapidly solidified solids. In this case, a strong electronic interaction between core and shared atoms is demonstrated to play a key role in the aggregation of inheritable icosahedral basic clusters. (C) 2014 Elsevier B.V. All rights reserved.
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