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QuAcK/src/GF/RGF2_self_energy_diag.f90
2024-09-03 16:28:18 +02:00

73 lines
1.6 KiB
Fortran

subroutine RGF2_self_energy_diag(eta,nBas,nC,nO,nV,nR,e,ERI,SigC,Z)
! Compute diagonal part of the GF2 self-energy and its renormalization factor
implicit none
include 'parameters.h'
! Input variables
double precision,intent(in) :: eta
integer,intent(in) :: nBas
integer,intent(in) :: nC
integer,intent(in) :: nO
integer,intent(in) :: nV
integer,intent(in) :: nR
double precision,intent(in) :: e(nBas)
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
! Local variables
integer :: i,j,a,b
integer :: p
double precision :: eps
double precision :: num
! Output variables
double precision,intent(out) :: SigC(nBas)
double precision,intent(out) :: Z(nBas)
! Initialize
SigC(:) = 0d0
Z(:) = 0d0
! Compute GF2 self-energy
do p=nC+1,nBas-nR
do i=nC+1,nO
do j=nC+1,nO
do a=nO+1,nBas-nR
eps = e(p) + e(a) - e(i) - e(j)
num = (2d0*ERI(p,a,i,j) - ERI(p,a,j,i))*ERI(p,a,i,j)
SigC(p) = SigC(p) + num*eps/(eps**2 + eta**2)
Z(p) = Z(p) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
end do
end do
end do
end do
do p=nC+1,nBas-nR
do i=nC+1,nO
do a=nO+1,nBas-nR
do b=nO+1,nBas-nR
eps = e(p) + e(i) - e(a) - e(b)
num = (2d0*ERI(p,i,a,b) - ERI(p,i,b,a))*ERI(p,i,a,b)
SigC(p) = SigC(p) + num*eps/(eps**2 + eta**2)
Z(p) = Z(p) - num*(eps**2 - eta**2)/(eps**2 + eta**2)**2
end do
end do
end do
end do
Z(:) = 1d0/(1d0 - Z(:))
end subroutine