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mirror of https://github.com/pfloos/quack synced 2024-11-09 15:43:56 +01:00
quack/src/GW/static_screening_W.f90

59 lines
1.4 KiB
Fortran

subroutine static_kernel_W(eta,nBas,nC,nO,nV,nR,nS,lambda,ERI,Om,rho,W)
! Compute the second-order static BSE kernel for the resonant block (only for singlets!)
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
integer,intent(in) :: nS
double precision,intent(in) :: lambda
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
double precision,intent(in) :: Om(nS)
double precision,intent(in) :: rho(nBas,nBas,nS)
! Local variables
double precision :: chi
integer :: p,q,r,s
integer :: m
double precision :: dem
! Output variables
double precision,intent(out) :: W(nBas,nBas,nBas,nBas)
!------------------------------------------------
! Compute static screening (physicist's notation)
!------------------------------------------------
do p=1,nBas
do q=1,nBas
do r=1,nBas
do s=1,nBas
chi = 0d0
do m=1,nS
dem = Om(m)**2 + eta**2
chi = chi + rho(p,q,m)*rho(r,s,m)*Om(m)/dem
enddo
W(p,s,q,r) = - lambda*ERI(p,s,q,r) + 4d0*lambda*chi
enddo
enddo
enddo
enddo
end subroutine static_kernel_W