No data available.

Please log in to see this content.

You have no subscription access to this content.

No metrics data to plot.

The attempt to load metrics for this article has failed.

The attempt to plot a graph for these metrics has failed.

The full text of this article is not currently available.

Efficient solution of Poisson’s equation in linear combination of atomic orbitals (LCAO) electronic structure calculations

### Abstract

An accurate and efficient method is described for the evaluation of electrostatic contributions in LCAO electronic structure calculations. The charge density ρ(**r**) is decomposed into ρ^{(1)}(**r**), a component whose rapid variation near any nucleus reproduces that of ρ(**r**) to a very good approximation, and a remainder density δρ(**r**)≡ρ(**r**)−ρ^{(1)}(**r**), which is thereby guaranteed to be slowly varying in space. The power of the decomposition resides in the fact that ρ^{(1)}(**r**) can be expressed exactly as a sum of one‐center densities, without the use of any fit procedure. Because ρ^{(1)}(**r**) is a sum of one‐center multipolar densities, the Hartree potential is a function with a simple one‐dimensional integral representation, and its matrix elements can be obtained by performing one‐dimensional integrals over it. Since δρ(**r**) is spatially slowly varying, the Hartree potential to which it corresponds and the matrix elements of this potential can accurately be evaluated on a relatively coarse coordinate space mesh, using fast Fourier transforms. The method is illustrated via molecular structure calculations for N_{2} and NH_{3}. The calculations are accurate to a few percent when the required integrals over δρ(**r**) and δ*V*(**r**) are performed on a mesh of spacing 0.4 a.u. The N–N bond length and stretch frequency are found to equal 2.10 a.u. and 2.3×10^{3} cm^{−} ^{1}, respectively. The equilibrium N–H bond length and H–N–H angle are calculated to be 1.93 a.u. and 105°, respectively, while the NH_{3} inversion barrier turns out to equal 0.25 eV. These results are in good agreement with earlier calculations.

© 1984 American Institute of Physics

Received 12 April 1984
Accepted 28 August 1984

/content/aip/journal/jcp/81/12/10.1063/1.447587

http://aip.metastore.ingenta.com/content/aip/journal/jcp/81/12/10.1063/1.447587

Article metrics loading...

/content/aip/journal/jcp/81/12/10.1063/1.447587

1984-12-20

2016-10-01

Full text loading...

###
Most read this month

Article

content/aip/journal/jcp

Journal

5

3

Commenting has been disabled for this content