2020-03-15 20:33:18 +01:00
|
|
|
subroutine RMFL20_lda_correlation_energy(nEns,wEns,nGrid,weight,rho,Ec)
|
2019-03-13 11:07:31 +01:00
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
! Compute the restricted version of the Marut-Fromager-Loos weight-dependent correlation functional
|
|
|
|
! The RMFL20 is a two-state, single-weight correlation functional for spin-unpolarized systems
|
2019-03-13 11:07:31 +01:00
|
|
|
|
|
|
|
implicit none
|
|
|
|
include 'parameters.h'
|
|
|
|
|
|
|
|
! Input variables
|
|
|
|
|
|
|
|
integer,intent(in) :: nEns
|
|
|
|
double precision,intent(in) :: wEns(nEns)
|
|
|
|
integer,intent(in) :: nGrid
|
|
|
|
double precision,intent(in) :: weight(nGrid)
|
|
|
|
double precision,intent(in) :: rho(nGrid,nspin)
|
|
|
|
|
|
|
|
! Local variables
|
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
logical :: LDA_centered = .true.
|
2019-03-13 11:07:31 +01:00
|
|
|
integer :: iEns,isp
|
|
|
|
double precision :: EcLDA(nsp)
|
2020-03-15 20:33:18 +01:00
|
|
|
double precision,allocatable :: aMFL(:,:)
|
2019-03-13 11:07:31 +01:00
|
|
|
double precision,allocatable :: EceLDA(:,:)
|
|
|
|
|
|
|
|
! Output variables
|
|
|
|
|
|
|
|
double precision :: Ec(nsp)
|
|
|
|
|
|
|
|
! Allocation
|
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
allocate(aMFL(3,nEns),EceLDA(nsp,nEns))
|
2019-03-13 11:07:31 +01:00
|
|
|
|
|
|
|
! Parameters for weight-dependent LDA correlation functional
|
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
aMFL(1,1) = -0.0238184d0
|
|
|
|
aMFL(2,1) = +0.00540994d0
|
|
|
|
aMFL(3,1) = +0.0830766d0
|
2019-03-13 11:07:31 +01:00
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
aMFL(1,2) = -0.0144633d0
|
|
|
|
aMFL(2,2) = -0.0506019d0
|
|
|
|
aMFL(3,2) = +0.0331417d0
|
2019-03-13 11:07:31 +01:00
|
|
|
|
|
|
|
! Compute correlation energy for ground, singly-excited and doubly-excited states
|
|
|
|
|
|
|
|
do iEns=1,nEns
|
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
call elda_correlation_energy(nEns,aMFL(:,iEns),nGrid,weight(:),rho(:,:),EceLDA(:,iEns))
|
2019-03-13 11:07:31 +01:00
|
|
|
|
|
|
|
end do
|
|
|
|
|
|
|
|
! LDA-centered functional
|
|
|
|
|
|
|
|
EcLDA(:) = 0d0
|
|
|
|
|
|
|
|
if(LDA_centered) then
|
|
|
|
|
|
|
|
call VWN5_lda_correlation_energy(nGrid,weight(:),rho(:,:),EcLDA(:))
|
|
|
|
|
|
|
|
do iEns=1,nEns
|
|
|
|
do isp=1,nsp
|
|
|
|
|
|
|
|
EceLDA(isp,iEns) = EceLDA(isp,iEns) + EcLDA(isp) - EceLDA(isp,1)
|
|
|
|
|
|
|
|
end do
|
|
|
|
end do
|
|
|
|
|
|
|
|
end if
|
|
|
|
|
|
|
|
! Weight-denpendent functional for ensembles
|
|
|
|
|
|
|
|
Ec(:) = 0d0
|
|
|
|
|
|
|
|
do iEns=1,nEns
|
|
|
|
do isp=1,nsp
|
|
|
|
|
|
|
|
Ec(isp) = Ec(isp) + wEns(iEns)*EceLDA(isp,iEns)
|
|
|
|
|
|
|
|
end do
|
|
|
|
end do
|
|
|
|
|
2020-03-15 20:33:18 +01:00
|
|
|
end subroutine RMFL20_lda_correlation_energy
|