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quack/src/QuAcK/Bethe_Salpeter_A_matrix.f90

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2019-03-19 10:13:33 +01:00
subroutine Bethe_Salpeter_A_matrix(nBas,nC,nO,nV,nR,nS,ERI,Omega,rho,A_lr)
! Compute the extra term for Bethe-Salpeter equation for linear response
implicit none
include 'parameters.h'
! Input variables
integer,intent(in) :: nBas,nC,nO,nV,nR,nS
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
double precision,intent(in) :: Omega(nS),rho(nBas,nBas,nS)
! Local variables
double precision :: chi
integer :: i,j,a,b,ia,jb,kc
! Output variables
double precision,intent(out) :: A_lr(nS,nS)
ia = 0
do i=nC+1,nO
do a=nO+1,nBas-nR
ia = ia + 1
jb = 0
do j=nC+1,nO
do b=nO+1,nBas-nR
jb = jb + 1
chi = 0d0
do kc=1,nS
chi = chi + rho(i,j,kc)*rho(a,b,kc)/Omega(kc)
enddo
A_lr(ia,jb) = A_lr(ia,jb) - ERI(i,a,j,b) + 4d0*chi
enddo
enddo
enddo
enddo
end subroutine Bethe_Salpeter_A_matrix