excpbec – The Jülich KKR codes

public subroutine excpbec(rs, zeta, t, uu, vv, ww, ec, vcup, vcdn, llda, bet)

This subroutine evaluates the correlation energy per particle and spin-up and spin-dn correlation potentials within the Perdew-Burke- Ernzerhof GGA. It is a slightly modified version of K. Burke's official PBE subroutine.

Note

[a] J.P. Perdew, K. Burke, and M. Ernzerhof, Phys. Rev. Lett. 77, 3865 (1996). [b] J. P. Perdew, K. Burke, and Y. Wang, Phys. Rev. B54, 16533 (1996). [c] J. P. Perdew and Y. Wang, Phys. Rev. B45, 13244 (1992).

All input and output is in atomic units

Arguments

Type	Intent		Name
real(kind=dp),	intent(in)	::	rs	Wigner-Seitz radius $\left(\frac{3}{4\pi\left(\rho_{up}+\rho_{down}\right)}\right)^\frac{1}{3}$
real(kind=dp),	intent(in)	::	zeta	$Z=\frac{\rho_{up}-\rho_{down}}{\rho_{up}+\rho_{down}}$ relative spin polarization
real(kind=dp),	intent(in)	::	t	$\frac{\\| \nabla D\\|}{2S_K G D}$
real(kind=dp),	intent(in)	::	uu	$\frac{\nabla D \nabla\\|\nabla D \\|}{\left(2S_K G\right)^3 D^2}$
real(kind=dp),	intent(in)	::	vv	$\frac{\nabla^2 D}{\left(2S_K G\right)^2 D}$
real(kind=dp),	intent(in)	::	ww	$\frac{\nabla D \nabla Z}{\left(2S_K G\right)^2 D}$
real(kind=dp),	intent(out)	::	ec	correlation energy per particle
real(kind=dp),	intent(out)	::	vcup	spin-dn correlation potential Local Feri momentum $F_K = \left(3\pi^2\left(\rho_{up}+\rho_{down}\right)\right)^\frac{1}{3}$ Local screening momentum $S_K = \lef(\frac{4*F_K}{\pi}\right)^\frac{1}{2}$
real(kind=dp),	intent(out)	::	vcdn	spin-up correlation potential
integer,	intent(in)	::	llda
real(kind=dp),	intent(in)	::	bet	coefficient in gradient expansion for correlation, a.

excpbec Subroutine

Contents

public subroutine excpbec(rs, zeta, t, uu, vv, ww, ec, vcup, vcdn, llda, bet)

Arguments