10
1
mirror of https://github.com/pfloos/quack synced 2024-12-26 14:23:38 +01:00
QuAcK/src/eDFT/RMFL20_lda_exchange_potential.f90

59 lines
1.3 KiB
Fortran
Raw Normal View History

subroutine RMFL20_lda_exchange_potential(LDA_centered,nEns,wEns,nGrid,weight,nBas,AO,rho,Fx)
2020-03-15 14:33:53 +01:00
! Compute the restricted version of the weight-dependent MFL20 exchange potential
implicit none
include 'parameters.h'
! Input variables
logical,intent(in) :: LDA_centered
2020-03-15 14:33:53 +01:00
integer,intent(in) :: nEns
double precision,intent(in) :: wEns(nEns)
integer,intent(in) :: nGrid
double precision,intent(in) :: weight(nGrid)
integer,intent(in) :: nBas
double precision,intent(in) :: AO(nBas,nGrid)
double precision,intent(in) :: rho(nGrid)
! Local variables
integer :: mu,nu,iG
double precision :: Cxw
double precision :: r,vAO
! Output variables
double precision,intent(out) :: Fx(nBas,nBas)
2020-03-17 11:29:20 +01:00
! Weight-dependent Cx coefficient for RMFL20 exchange functional
2020-03-15 14:33:53 +01:00
2020-03-29 18:34:09 +02:00
if(LDA_centered) then
Cxw = CxLDA + (Cx1 - Cx0)*wEns(2)
else
Cxw = wEns(1)*Cx0 + wEns(2)*Cx1
end if
2020-03-15 14:33:53 +01:00
! Compute LDA exchange matrix in the AO basis
Fx(:,:) = 0d0
2020-03-31 12:39:26 +02:00
2020-03-15 14:33:53 +01:00
do mu=1,nBas
do nu=1,nBas
do iG=1,nGrid
r = max(0d0,rho(iG))
if(r > threshold) then
vAO = weight(iG)*AO(mu,iG)*AO(nu,iG)
Fx(mu,nu) = Fx(mu,nu) + vAO*4d0/3d0*Cxw*r**(1d0/3d0)
endif
enddo
enddo
enddo
end subroutine RMFL20_lda_exchange_potential