From 5df79c53745fde5d6c3340a2979b1429cd5892c1 Mon Sep 17 00:00:00 2001 From: Henrik Rydberg Date: Sat, 8 Oct 2011 20:30:28 +0200 Subject: Initial import of htcd system 1.0 Signed-off-by: Henrik Rydberg --- src/labat/gga.f | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 src/labat/gga.f (limited to 'src/labat/gga.f') diff --git a/src/labat/gga.f b/src/labat/gga.f new file mode 100644 index 0000000..083fdad --- /dev/null +++ b/src/labat/gga.f @@ -0,0 +1,45 @@ +c***************************************************************** +c***************************************************************** +c***************************************************************** +c GGA +c The Generalized Gradient Approximation + +c GGA is a way to improve the local spin density approximation +c by adding nonlocal gradients in the evaluation of the exchange- +c correlation energy and potential. These functions and subroutines +c are based on programs made by John Perdew, Tulane University, +c New Orleans, Louisiana, USA. Email: PY03APF%music.tcs.tulane.edu +c The modifications necessary to fit them to the atom program was +c made by Tomas Holmquist 1993 (so now you know who to blame). +c Email: tomash@fy.chalmers.se +c A more thorough description of the GGA used may be found in +c J.P. Perdew et al, Phys. Rev. B (46) 1992 pp. 6671-6687. + +c The GGA package is: + +c function deriv +c subroutine grad +c subroutine grabgr +c subroutine laplac +c subroutine spline +c subroutine splint +c subroutine ggaexc +c subroutine exchen +c subroutine ldaec +c subroutine gcor +c subroutine ggaec +c subroutine ggauxc +c subroutine exchpt +c subroutine ldauc +c subroutine ggauc + +c The grad, grabgr, and laplace subroutines uses the function deriv +c to calculate different derivatives with respect to the radial +c coordinate r. Spline and splint calculates the cubic spline +c interpolation which is used in function deriv. +c The two main subprograms, ggaexc and ggauxc, calculates +c the exchange-correlation energy and potential respectively. +c The other subroutines are modified versions of Perdew's program. + +c***************************************************************** +c***************************************************************** -- cgit v1.2.3