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mirror of https://github.com/pfloos/quack synced 2025-05-06 23:34:42 +02:00
quack/src/GF/cRGF2_Im_SigC.f90
2025-04-14 14:07:18 +02:00

60 lines
1.6 KiB
Fortran

double precision function cRGF2_Im_SigC(p,Re_w,Im_w,eta,nBas,nC,nO,nV,nR,eHF,e_cap,ERI)
! Compute diagonal of the correlation part of the self-energy
implicit none
include 'parameters.h'
! Input variables
integer,intent(in) :: p
double precision,intent(in) :: Re_w
double precision,intent(in) :: Im_w
double precision,intent(in) :: eta
integer,intent(in) :: nBas,nC,nO,nV,nR
double precision,intent(in) :: eHF(nBas)
double precision,intent(in) :: e_cap(nBas)
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
! Local variables
integer :: i,j,a,b
double precision :: eps
double precision :: eta_tilde
double precision :: num
! Initialize
cRGF2_Im_SigC = 0d0
! Occupied part of the correlation self-energy
do i=nC+1,nO
do j=nC+1,nO
do a=nO+1,nBas-nR
eps = Re_w + eHF(a) - eHF(i) - eHF(j)
eta_tilde = eta - Im_w + e_cap(i) -( e_cap(a) - e_cap(j))
num = (2d0*ERI(p,a,i,j) - ERI(p,a,j,i))*ERI(p,a,i,j)
cRGF2_Im_SigC = cRGF2_Im_SigC + num*eta_tilde/(eps**2 + eta_tilde**2)
end do
end do
end do
! Virtual part of the correlation self-energy
do i=nC+1,nO
do a=nO+1,nBas-nR
do b=nO+1,nBas-nR
eps = Re_w + eHF(i) - eHF(a) - eHF(b)
num = (2d0*ERI(p,i,a,b) - ERI(p,i,b,a))*ERI(p,i,a,b)
eta_tilde = eta + Im_w - e_cap(a) - e_cap(b) + e_cap(i)
cRGF2_Im_SigC = cRGF2_Im_SigC - num*eta_tilde/(eps**2 + eta_tilde**2)
end do
end do
end do
end function