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QuAcK/src/MBPT/Sangalli_A_matrix_dynamic.f90.x

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2020-10-21 12:59:02 +02:00
subroutine Sangalli_A_matrix_dynamic(eta,nBas,nC,nO,nV,nR,nS,lambda,eGW,OmRPA,OmBSE,rho,A_dyn)
! Compute the dynamic part of the Bethe-Salpeter equation matrices
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) :: eGW(nBas)
double precision,intent(in) :: OmRPA(nS)
double precision,intent(in) :: OmBSE
double precision,intent(in) :: rho(nBas,nBas,nS)
! Local variables
integer :: maxS
double precision :: chi
double precision :: eps
integer :: i,j,a,b,ia,jb,kc
! Output variables
double precision,intent(out) :: A_dyn(nS,nS)
! Initialization
A_dyn(:,:) = 0d0
! Number of poles taken into account
maxS = nS
! Build dynamic A matrix
do
(ERI(i,k,j,c)*KroneckerDelta(a,b) + ERI(k,a,c,b)*KroneckerDelta(i,j))*(X)
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,maxS
chi = chi + rho(i,j,kc)*rho(a,b,kc)*OmRPA(kc)/(OmRPA(kc)**2 + eta**2)
enddo
A_dyn(ia,jb) = A_dyn(ia,jb) - 4d0*lambda*chi
chi = 0d0
do kc=1,maxS
do ld=1,maxS
eps = OmBSE - (OmRPA(kc) + OmRPA(ld))
chi = chi + cRPA(ia,kc,ld)*cRPA(jb,kc,ld)*eps/(eps**2 + (2d0*eta)**2)
enddo
A_dyn(ia,jb) = A_dyn(ia,jb) - 2d0*lambda*chi
enddo
enddo
enddo
enddo
end subroutine Sangalli_A_matrix_dynamic