The spin-density-functional formalism for quantum mechanical calculations: Test on diatomic molecules with an efficient numerical method
✍ Scribed by O. Gunnarsson; P. Johansson
- Publisher
- John Wiley and Sons
- Year
- 1976
- Tongue
- English
- Weight
- 957 KB
- Volume
- 10
- Category
- Article
- ISSN
- 0020-7608
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✦ Synopsis
Abstract
We have applied the spin‐density‐functional (SDF) formalism with the local‐spin‐density (LSD) approximation to a number of small molecules with the primary aim of testing the approximation for molecular applications. A new numerical method to solve the one‐electron wave equation is developed, utilizing the special features of the SDF formalism. We have calculated energy curves, dissociation energies, and equilibrium distances for some diatomic molecules [H (^2^Σ, ^2^Σ), H~2~(^1^Σ, ^3^Σ), He (^1^Σ), and He~2~(^1^Σ)] and the vibrational frequencies of H~2~. The deviations from the experimental results are typically 1/2 eV for the energies and ≤ 0.1 Å for the distances. We discuss the LSD approximation using the concept of an exchange‐correlation hole and make predictions about the applicability to other molecules. The LSD approximation is compared with the Hartree‐Fock and multiple‐scattering‐__X__α methods and some difficulties in the latter methods are pointed out. It is argued that the SDF formalism within the LSD approximation has physical advantages compared to the Hartree‐Fock and __X__α methods and that it should provide a simple and useful method for a broad range of applications.