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mirror of https://github.com/pfloos/quack synced 2024-12-25 13:53:41 +01:00
QuAcK/src/MBPT/self_energy_correlation.f90

101 lines
2.2 KiB
Fortran

subroutine self_energy_correlation(COHSEX,eta,nBas,nC,nO,nV,nR,nS,e,Omega,rho,EcGM,SigC)
! Compute correlation part of the self-energy
implicit none
include 'parameters.h'
! Input variables
logical,intent(in) :: COHSEX
double precision,intent(in) :: eta
integer,intent(in) :: nBas,nC,nO,nV,nR,nS
double precision,intent(in) :: e(nBas)
double precision,intent(in) :: Omega(nS)
double precision,intent(in) :: rho(nBas,nBas,nS)
! Local variables
integer :: i,j,a,b,p,x,y,jb
double precision :: eps
! Output variables
double precision,intent(out) :: SigC(nBas,nBas)
double precision,intent(out) :: EcGM
! Initialize
SigC = 0d0
!-----------------------------!
! COHSEX static approximation !
!-----------------------------!
if(COHSEX) then
! COHSEX: SEX of the COHSEX correlation self-energy
do x=nC+1,nBas-nR
do y=nC+1,nBas-nR
do i=nC+1,nO
do jb=1,nS
SigC(x,y) = SigC(x,y) + 4d0*rho(x,i,jb)*rho(y,i,jb)/Omega(jb)
enddo
enddo
enddo
enddo
! COHSEX: COH part of the COHSEX correlation self-energy
do x=nC+1,nBas-nR
do y=nC+1,nBas-nR
do p=nC+1,nBas-nR
do jb=1,nS
SigC(x,y) = SigC(x,y) - 2d0*rho(x,p,jb)*rho(y,p,jb)/Omega(jb)
enddo
enddo
enddo
enddo
EcGM = 0d0
do i=nC+1,nO
EcGM = EcGM + 0.5d0*SigC(i,i)
enddo
else
!----------------!
! GW self-energy !
!----------------!
! Occupied part of the correlation self-energy
do x=nC+1,nBas-nR
do y=nC+1,nBas-nR
do i=nC+1,nO
do jb=1,nS
eps = e(x) - e(i) + Omega(jb)
SigC(x,y) = SigC(x,y) + 2d0*rho(x,i,jb)*rho(y,i,jb)*eps/(eps**2 + eta**2)
enddo
enddo
enddo
enddo
! Virtual part of the correlation self-energy
do x=nC+1,nBas-nR
do y=nC+1,nBas-nR
do a=nO+1,nBas-nR
do jb=1,nS
eps = e(x) - e(a) - Omega(jb)
SigC(x,y) = SigC(x,y) + 2d0*rho(x,a,jb)*rho(y,a,jb)*eps/(eps**2 + eta**2)
enddo
enddo
enddo
enddo
endif
end subroutine self_energy_correlation