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QuAcK/src/GF/GGF2_phBSE_static_kernel_A.f90

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subroutine GGF2_phBSE_static_kernel_A(eta,nBas,nC,nO,nV,nR,nS,lambda,ERI,eGF,KA_sta)
! Compute the resonant part of the static BSE@GF2 matrix
implicit none
include 'parameters.h'
! Input variables
integer,intent(in) :: nBas,nC,nO,nV,nR,nS
double precision,intent(in) :: eta
double precision,intent(in) :: lambda
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
double precision,intent(in) :: eGF(nBas)
! Local variables
double precision :: dem,num
integer :: i,j,k,l
integer :: a,b,c,d
integer :: ia,jb
! Output variables
double precision,intent(out) :: KA_sta(nS,nS)
! Initialization
KA_sta(:,:) = 0d0
! Second-order correlation kernel for the block A of the spinorbital manifold
jb = 0
!$omp parallel do default(private) shared(KA_sta,ERI,num,dem,eGF,nO,nBas,eta,nC,nR)
do j=nC+1,nO
do b=nO+1,nBas-nR
jb = (b-nO) + (j-1)*(nBas-nO)
ia = 0
do i=nC+1,nO
do a=nO+1,nBas-nR
ia = (a-nO) + (i-1)*(nBas-nO)
do k=nC+1,nO
do c=nO+1,nBas-nR
dem = - (eGF(c) - eGF(k))
num = ERI(j,k,i,c)*ERI(a,c,b,k) - ERI(j,k,i,c)*ERI(a,c,k,b) &
- ERI(j,k,c,i)*ERI(a,c,b,k) + ERI(j,k,c,i)*ERI(a,c,k,b)
KA_sta(ia,jb) = KA_sta(ia,jb) - num*dem/(dem**2 + eta**2)
dem = + (eGF(c) - eGF(k))
num = ERI(j,c,i,k)*ERI(a,k,b,c) - ERI(j,c,i,k)*ERI(a,k,c,b) &
- ERI(j,c,k,i)*ERI(a,k,b,c) + ERI(j,c,k,i)*ERI(a,k,c,b)
KA_sta(ia,jb) = KA_sta(ia,jb) + num*dem/(dem**2 + eta**2)
end do
end do
do c=nO+1,nBas-nR
do d=nO+1,nBas-nR
dem = - (eGF(c) + eGF(d))
num = ERI(a,j,c,d)*ERI(c,d,i,b) - ERI(a,j,c,d)*ERI(c,d,b,i) &
- ERI(a,j,d,c)*ERI(c,d,i,b) + ERI(a,j,d,c)*ERI(c,d,b,i)
KA_sta(ia,jb) = KA_sta(ia,jb) + 0.5d0*num*dem/(dem**2 + eta**2)
end do
end do
do k=nC+1,nO
do l=nC+1,nO
dem = - (eGF(k) + eGF(l))
num = ERI(a,j,k,l)*ERI(k,l,i,b) - ERI(a,j,k,l)*ERI(k,l,b,i) &
- ERI(a,j,l,k)*ERI(k,l,i,b) + ERI(a,j,l,k)*ERI(k,l,b,i)
KA_sta(ia,jb) = KA_sta(ia,jb) - 0.5d0*num*dem/(dem**2 + eta**2)
end do
end do
end do
end do
end do
end do
!$omp end parallel do
end subroutine