LOCAL STRUCTURE OF SOLID SOLUTIONS FROM THE COMPUTER SIMULATION RESULTS AND EXPERIMENTAL DATA
V. S. Urusov†, N. N. Eremin
Moscow State University, Moscow, Russia
Keywords: атомистическое компьютерное моделирование, твердые растворы замещения, локальная структура, параметр релаксации, податливость позиции, межатомные расстояния, объемы полиэдров, atomistic computer simulation, solid substitution solutions, local structure, relaxation parameter, site compliance, interatomic distances, polyhedral volumes
Abstract
The possibilities of studying the local structure in isomorphic systems by methods based on the minimization of the interatomic interaction energy are considered in the work. The original procedure for the theoretical analysis of the local structure, which the authors have been developing for a number of years and have implemented in four computer programs, is discussed in detail. The practical implementation of this procedure is exemplified by the following solid substitution solutions: halite-sylvin (Na,K)Cl, corundum-eskolaite (Al,Cr)2O3, spinel-magnesiochromite Mg(Al,Cr)2O4, chrysoberyl-mariinskite Be(Al,Сr)2O4, grossular-uvarovite Ca3(Al,Cr)2[SiO4]3. Calculations are performed on a SKIF MGU Chebyshev supercomputer for supercells containing several thousands of atoms. The performed analysis of the behavior of changes in the geometric characteristics of CrO 6 octahedra in various isomorphic systems makes it possible to reveal the main reasons affecting the alteration of the relaxation parameter. It is found that the key factor is the size of the common structural unit of an isomorphic mixture. Thus, the behavior of the relaxation parameter obeys the isomorphism assistance rule.
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