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Chemical binding in small molecules by the spin‐density‐functional formalism
Author(s) -
Gunnarsson O.,
Johansson P.,
Lundqvist S.,
Lundqvist B. I.
Publication year - 2009
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.560090814
Subject(s) - formalism (music) , scattering , spin density , molecule , density functional theory , local density approximation , valence (chemistry) , physics , electronic structure , quantum mechanics , statistical physics , chemistry , atomic physics , condensed matter physics , art , musical , visual arts
A brief review is given of some results within the spin‐density‐functional ( SDF ) formalism. The local‐spin‐density ( LSD ) approximation, that is, the approximation which is formally exact in the limit of slow and weak spatial variations, gives results of a useful accuracy for valence electrons in atoms and solids, and the accuracy for molecules may be illustrated by the hydrogen‐molecule energy curves in the lowest 1 Σ + θ and 3 Σ + u states being about 0.3 eV from the exact result. Good results are obtained for H + 3 , H 3 and H ‐ 3 , too. Applications to He + 2 and He 2+ 2 inform about the range of applicability of the approximation. Further, the new numerical method developed for these molecular applications allows an evaluation of the multiple‐scattering X α method, showing shortcomings of both the potential and the multiple‐scattering approach used in this method. We argue that the SDF formalism within the LSD approximation is physically superior to the X α method and provides a simple and useful method for applications within a broad range, such as calculations on molecules and chemisorption systems.