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mirror of https://github.com/pfloos/quack synced 2024-11-19 04:22:39 +01:00
quack/src/GF/GF2_self_energy.f90

74 lines
1.7 KiB
Fortran

subroutine GF2_self_energy(eta,nBas,nC,nO,nV,nR,nS,eHF,eGF2,ERI,SigC,Z)
! Compute GF2 self-energy and its renormalization factor
implicit none
include 'parameters.h'
! Input variables
double precision,intent(in) :: eta
integer,intent(in) :: nBas,nC,nO,nV,nR,nS
double precision,intent(in) :: eHF(nBas)
double precision,intent(in) :: eGF2(nBas)
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
! Local variables
integer :: i,j,a,b
integer :: p,q
double precision :: eps
double precision :: num
! Output variables
double precision,intent(out) :: SigC(nBas,nBas)
double precision,intent(out) :: Z(nBas)
! Initialize
SigC(:,:) = 0d0
Z(:) = 0d0
! Compute GF2 self-energy and renormalization factor
do p=nC+1,nBas-nR
do q=nC+1,nBas-nR
do i=nC+1,nO
do j=nC+1,nO
do a=nO+1,nBas-nR
eps = eGF2(p) + eHF(a) - eHF(i) - eHF(j)
num = (2d0*ERI(p,a,i,j) - ERI(p,a,j,i))*ERI(q,a,i,j)
SigC(p,q) = SigC(p,q) + num*eps/(eps**2 + eta**2)
if(p == q) Z(p) = Z(p) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
end do
end do
end do
end do
end do
do p=nC+1,nBas-nR
do q=nC+1,nBas-nR
do i=nC+1,nO
do a=nO+1,nBas-nR
do b=nO+1,nBas-nR
eps = eGF2(p) + eHF(i) - eHF(a) - eHF(b)
num = (2d0*ERI(p,i,a,b) - ERI(p,i,b,a))*ERI(q,i,a,b)
SigC(p,q) = SigC(p,q) + num*eps/(eps**2 + eta**2)
if(p == q) Z(p) = Z(p) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
end do
end do
end do
end do
end do
Z(:) = 1d0/(1d0 - Z(:))
end subroutine