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https://github.com/pfloos/quack
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82 lines
1.8 KiB
Fortran
82 lines
1.8 KiB
Fortran
subroutine RMFL20_lda_correlation_energy(nEns,wEns,nGrid,weight,rho,Ec)
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! Compute the restricted version of the Marut-Fromager-Loos weight-dependent correlation functional
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! The RMFL20 is a two-state, single-weight correlation functional for spin-unpolarized systems
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implicit none
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include 'parameters.h'
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! Input variables
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integer,intent(in) :: nEns
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double precision,intent(in) :: wEns(nEns)
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integer,intent(in) :: nGrid
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double precision,intent(in) :: weight(nGrid)
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double precision,intent(in) :: rho(nGrid,nspin)
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! Local variables
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logical :: LDA_centered = .true.
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integer :: iEns,isp
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double precision :: EcLDA(nsp)
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double precision,allocatable :: aMFL(:,:)
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double precision,allocatable :: EceLDA(:,:)
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! Output variables
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double precision :: Ec(nsp)
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! Allocation
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allocate(aMFL(3,nEns),EceLDA(nsp,nEns))
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! Parameters for weight-dependent LDA correlation functional
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aMFL(1,1) = -0.0238184d0
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aMFL(2,1) = +0.00540994d0
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aMFL(3,1) = +0.0830766d0
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aMFL(1,2) = -0.0144633d0
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aMFL(2,2) = -0.0506019d0
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aMFL(3,2) = +0.0331417d0
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! Compute correlation energy for ground, singly-excited and doubly-excited states
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do iEns=1,nEns
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call elda_correlation_energy(nEns,aMFL(:,iEns),nGrid,weight(:),rho(:,:),EceLDA(:,iEns))
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end do
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! LDA-centered functional
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EcLDA(:) = 0d0
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if(LDA_centered) then
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call VWN5_lda_correlation_energy(nGrid,weight(:),rho(:,:),EcLDA(:))
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do iEns=1,nEns
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do isp=1,nsp
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EceLDA(isp,iEns) = EceLDA(isp,iEns) + EcLDA(isp) - EceLDA(isp,1)
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end do
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end do
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end if
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! Weight-denpendent functional for ensembles
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Ec(:) = 0d0
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do iEns=1,nEns
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do isp=1,nsp
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Ec(isp) = Ec(isp) + wEns(iEns)*EceLDA(isp,iEns)
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end do
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end do
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end subroutine RMFL20_lda_correlation_energy
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