mirror of https://github.com/pfloos/quack
135 lines
3.3 KiB
Fortran
135 lines
3.3 KiB
Fortran
subroutine UGW_self_energy(eta,nBas,nC,nO,nV,nR,nSt,e,Om,rho,Sig,Z,EcGM)
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! Compute diagonal of the correlation part of the self-energy
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implicit none
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include 'parameters.h'
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! Input variables
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double precision,intent(in) :: eta
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integer,intent(in) :: nBas
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integer,intent(in) :: nC(nspin)
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integer,intent(in) :: nO(nspin)
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integer,intent(in) :: nV(nspin)
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integer,intent(in) :: nR(nspin)
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integer,intent(in) :: nSt
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double precision,intent(in) :: e(nBas,nspin)
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double precision,intent(in) :: Om(nSt)
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double precision,intent(in) :: rho(nBas,nBas,nSt,nspin)
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! Local variables
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integer :: i,a,p,q,m
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double precision :: num,eps
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! Output variables
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double precision,intent(out) :: Sig(nBas,nBas,nspin)
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double precision,intent(out) :: Z(nBas,nspin)
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double precision :: EcGM(nspin)
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! Initialize
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Sig(:,:,:) = 0d0
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Z(:,:) = 0d0
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EcGM(:) = 0d0
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!--------------!
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! Spin-up part !
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!--------------!
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! Occupied part of the correlation self-energy
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do p=nC(1)+1,nBas-nR(1)
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do q=nC(1)+1,nBas-nR(1)
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do i=nC(1)+1,nO(1)
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do m=1,nSt
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eps = e(p,1) - e(i,1) + Om(m)
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num = rho(p,i,m,1)*rho(q,i,m,1)
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Sig(p,q,1) = Sig(p,q,1) + num*eps/(eps**2 + eta**2)
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if(p == q) Z(p,1) = Z(p,1) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
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end do
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end do
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end do
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end do
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! Virtual part of the correlation self-energy
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do p=nC(1)+1,nBas-nR(1)
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do q=nC(1)+1,nBas-nR(1)
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do a=nO(1)+1,nBas-nR(1)
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do m=1,nSt
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eps = e(p,1) - e(a,1) - Om(m)
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num = rho(p,a,m,1)*rho(q,a,m,1)
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Sig(p,q,1) = Sig(p,q,1) + num*eps/(eps**2 + eta**2)
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if(p == q) Z(p,1) = Z(p,1) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
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end do
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end do
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end do
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end do
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! GM correlation energy
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do i=nC(1)+1,nO(1)
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do a=nO(1)+1,nBas-nR(1)
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do m=1,nSt
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eps = e(a,1) - e(i,1) + Om(m)
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num = rho(a,i,m,1)**2
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EcGM(1) = EcGM(1) - num*eps/(eps**2 + eta**2)
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end do
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end do
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end do
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!----------------!
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! Spin-down part !
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!----------------!
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! Occupied part of the correlation self-energy
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do p=nC(2)+1,nBas-nR(2)
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do q=nC(2)+1,nBas-nR(2)
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do i=nC(2)+1,nO(2)
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do m=1,nSt
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eps = e(p,2) - e(i,2) + Om(m)
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num = rho(p,i,m,2)*rho(q,i,m,2)
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Sig(p,q,2) = Sig(p,q,2) + num*eps/(eps**2 + eta**2)
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if(p == q) Z(p,2) = Z(p,2) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
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end do
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end do
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end do
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end do
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! Virtual part of the correlation self-energy
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do p=nC(2)+1,nBas-nR(2)
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do q=nC(2)+1,nBas-nR(2)
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do a=nO(2)+1,nBas-nR(2)
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do m=1,nSt
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eps = e(p,2) - e(a,2) - Om(m)
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num = rho(p,a,m,2)*rho(q,a,m,2)
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Sig(p,q,2) = Sig(p,q,2) + num*eps/(eps**2 + eta**2)
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if(p == q) Z(p,2) = Z(p,2) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
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end do
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end do
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end do
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end do
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! GM correlation energy
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do i=nC(2)+1,nO(2)
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do a=nO(2)+1,nBas-nR(2)
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do m=1,nSt
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eps = e(a,2) - e(i,2) + Om(m)
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num = rho(a,i,m,2)**2
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EcGM(2) = EcGM(2) - num*eps/(eps**2 + eta**2)
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end do
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end do
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end do
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! Compute renormalization factor from derivative
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Z(:,:) = 1d0/(1d0 - Z(:,:))
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end subroutine
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