Spin--density-functional formalism for quantum mechanical calculations: test on diatomic molecules with an efficient numerical method

Journal Article · Mon Mar 01 04:00:00 EST 1976 · Int. J. Quant. Chem., v. 10, no. 2, pp. 307-323

DOI:https://doi.org/10.1002/qua.560100210· OSTI ID:4022874

Gunnarsson, O; Johansson, P

The spin-density-functional (SDF) formalism with the local-spin-density (LSD) approximation is applied 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. Energy curves, dissociation energies, and equilibrium distances for some diatomic molecules [H$sub 2$$sup +$$($$sup 2$$Sigma$$sup +$/sub g/, $sup 2$$Sigma$$sup +$/sub u/), H$sub 2$$($$sup 1$$Sigma$$sup +$/sub g/, $sup 3$$Sigma$$sup +$/sub u/), He$sub 2$$sup 2+$$($$sup 1$$Sigma$$sup +$/sub g/), and He$sub 2$$($$sup 1$$Sigma$$sup +$/sub g/)] and the vibrational frequencies of H$sub 2$. The deviations from the experimental results are typically $sup 1$$/$$sub 2$ eV for the energies and less than or equal to 0.1 A for the distances. The LSD approximation is discussed using the concept of an exchange-correlation hole and predictions about the applicability to other molecules are made. The LSD approximation is compared with the Hartree--Fock and multiple-scattering-X$alpha$ 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$alpha$ methods and that it should provide a simple and useful method for a broad range of applications. (auth)

• Research Organization: Chalmers Univ. of Tech., Goteborg
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-031070
• OSTI ID: 4022874
• Journal Information: Int. J. Quant. Chem., v. 10, no. 2, pp. 307-323, Journal Name: Int. J. Quant. Chem., v. 10, no. 2, pp. 307-323; ISSN IJQCB
• Country of Publication: United States
• Language: English

Related Subjects

*DEUTERIUM-- ELECTRONIC STRUCTURE
*HELIUM IONS-- ELECTRONIC STRUCTURE
*HELIUM-- VIBRATIONAL STATES
*HYDROGEN IONS 2 PLUS-- ELECTRONIC STRUCTURE
640302* --Physics Research--Atomic
Molecular & Chemical Physics--Atomic & Molecular Properties
CORRELATIONS
DISTANCE
ENERGY
EQUILIBRIUM
FUNCTIONALS
HOLES
MOLECULES
N60200* --Physics (Atomic & Molecular)--Atomic & Molecular Properties
QUANTUM MECHANICS
SPIN
WAVE FUNCTIONS