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Effects of exchange on equilibrium bond lengths of heavy, almost spherical, tetrahedral molecules XH 4
Author(s) -
Egorov S. A.,
March N. H.,
Santamaria R.
Publication year - 1992
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560420603
Subject(s) - bond length , atom (system on chip) , chemistry , tetrahedron , molecular geometry , thomas–fermi model , molecule , atomic number , bond energy , physics , dirac (video compression format) , atomic physics , quantum mechanics , crystallography , computer science , neutrino , embedded system , electron
Abstract The simplest nonrelativistic density functional theory, namely, that of Thomas, Fermi, and Dirac, is used to study the effect of exchange on the equilibrium bond lengths of heavy tetrahedral molecules XH 4 . In particular, the limiting bond length as the central atom X becomes infinitely heavy is shown to be reduced by exchange by some 0.34 Å. Comparison with experiment shows that the main features of the bond‐length variation through the series CH 4 PbH 4 are reflected by the Thomas–Fermi–Dirac predictions, though the bond lengths remain too large for finite atomic number Z of the central atom. Therefore, a semiempirical correction is proposed, which, however, tends to zero as Z tends to infinity.