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https://github.com/pfloos/quack
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84 lines
2.0 KiB
Fortran
84 lines
2.0 KiB
Fortran
subroutine self_energy_correlation_SRG(eta,nBas,nC,nO,nV,nR,nS,e,Omega,rho,EcGM,SigC)
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! Compute 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
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integer,intent(in) :: nO
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integer,intent(in) :: nV
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integer,intent(in) :: nR
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integer,intent(in) :: nS
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double precision,intent(in) :: e(nBas)
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double precision,intent(in) :: Omega(nS)
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double precision,intent(in) :: rho(nBas,nBas,nS)
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! Local variables
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integer :: i,j,a,b
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integer :: p,q,r
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integer :: m
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double precision :: Dpim,Dqim,Dpam,Dqam
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! Output variables
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double precision,intent(out) :: EcGM
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double precision,intent(out) :: SigC(nBas,nBas)
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! Initialize
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SigC(:,:) = 0d0
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!--------------------!
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! SRG-GW self-energy !
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!--------------------!
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! Occupied part of the correlation self-energy
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do m=1,nS
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do i=nC+1,nO
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do q=nC+1,nBas-nR
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do p=nC+1,nBas-nR
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Dpim = e(p) - e(i) + Omega(m)
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Dqim = e(q) - e(i) + Omega(m)
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SigC(p,q) = SigC(p,q) + 2d0*rho(p,i,m)*rho(q,i,m)*(1-exp(-eta*Dpim**2)*exp(-eta*Dqim**2)) &
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*(Dpim + Dqim)/(Dpim**2 + Dqim**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 m=1,nS
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do a=nO+1,nBas-nR
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do q=nC+1,nBas-nR
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do p=nC+1,nBas-nR
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Dpam = e(p) - e(a) - Omega(m)
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Dqam = e(q) - e(a) - Omega(m)
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SigC(p,q) = SigC(p,q) + 2d0*rho(p,a,m)*rho(q,a,m)*(1-exp(-eta*Dpam**2)*exp(-eta*Dqam**2)) &
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*(Dpam + Dqam)/(Dpam**2 + Dqam**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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! Galitskii-Migdal correlation energy
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EcGM = 0d0
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! do i=nC+1,nO
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! do a=nO+1,nBas-nR
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! do m=1,nS
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! EcGM = EcGM - 4d0*rho(a,i,jb)*rho(a,i,jb)*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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end subroutine self_energy_correlation_SRG
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