On the calculation of atomization energies of organic molecules in the Xα local spin density approximation

1988 ◽  
Vol 66 (12) ◽  
pp. 3166-3170 ◽  
Author(s):  
S. Fliszàr ◽  
S. Rioux ◽  
J. Andzelm ◽  
C. Minichino ◽  
E. C. Vauthier
Keyword(s):  
Spin Density ◽  
Organic Molecules ◽  
Correlation Energy ◽  
Local Spin Density Approximation ◽  
Potential Minimum ◽  
Alkyl Radicals ◽  
Exchange Correlation ◽  
Local Spin ◽  
Energy Formula ◽  
Additivity Rules

The atomization energies of selected alkanes, alkyl radicals, and amines are deduced from Xα local spin density calculations of E, the total energy of a molecule in its potential minimum. Both the exchange-correlation energy, [Formula: see text], and [Formula: see text] itself obey, in a first approximation, simple atom-by-atom additivity rules. The appropriate α's for use in Xα(LSD) calculations of organic molecules thus appear as weighted averages and depend on the particular composition of each molecule. The at least approximate validity of this averaging procedure is illustrated by the accuracy of calculated atomization energies.

scholarly journals Accurate spin-dependent electron liquid correlation energies for local spin density calculations: a critical analysis

1980 ◽  
Vol 58 (8) ◽  
pp. 1200-1211 ◽  
Author(s):  
S. H. Vosko ◽  
L. Wilk ◽  
M. Nusair
Keyword(s):  
Spin Density ◽  
Correlation Energy ◽  
Electron Gas ◽  
Interpolation Formula ◽  
Maximum Error ◽  
Energy Functional ◽  
Local Spin Density Approximation ◽  
Density Approximation ◽  
Local Spin ◽  
Spin Polarized

We assess various approximate forms for the correlation energy per particle of the spin-polarized homogeneous electron gas that have frequently been used in applications of the local spin density approximation to the exchange-correlation energy functional. By accurately recalculating the RPA correlation energy as a function of electron density and spin polarization we demonstrate the inadequacies of the usual approximation for interpolating between the para- and ferro-magnetic states and present an accurate new interpolation formula. A Padé approximant technique is used to accurately interpolate the recent Monte Carlo results (para and ferro) of Ceperley and Alder into the important range of densities for atoms, molecules, and metals. These results can be combined with the RPA spin-dependence so as to produce a correlation energy for a spin-polarized homogeneous electron gas with an estimated maximum error of 1 mRy and thus should reliably determine the magnitude of non-local corrections to the local spin density approximation in real systems.

Sign in / Sign up

Export Citation Format

Share Document