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Short‐Range Three‐Body Potential in the First‐Order Exchange Energy and the Relative Stability of Alkali Halide Crystals
Author(s) -
Paul S.,
Sarkar A. K.,
Sengupta S.
Publication year - 1972
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220540132
Subject(s) - halide , alkali metal , atomic physics , expression (computer science) , helium , range (aeronautics) , argon , ion , xenon , chemistry , potential energy , binding energy , stability (learning theory) , physics , materials science , quantum mechanics , inorganic chemistry , machine learning , computer science , composite material , programming language
Using the Heitler‐London approach a simple expression for the first‐order exchange energy between a system of interacting atoms or ions is obtained in the S 2 approximation. It is shown that this expression leads to two‐body, three‐body, and four‐body interactions only. A specific expression for the three‐body interaction is evaluated using several different approximations. Assumptions which lead to the expression previously obtained by Lundqvist are discussed. It is found that these expressions vanish for neutral particles. Some modification in the assumption is made and an expression for three‐body interaction for neutral particles is obtained. Numerical calculations are made for argon, xenon, and helium and the results compared with those obtained by others. The three‐body interaction is also applied to study the relative stability of different alkali halide structures. It is found that this three‐body potential has a strong preference for CsCl structure.