mirror of
https://github.com/pfloos/quack
synced 2024-12-24 21:33:45 +01:00
51 lines
1.3 KiB
Fortran
51 lines
1.3 KiB
Fortran
subroutine Bethe_Salpeter_B_matrix(eta,nBas,nC,nO,nV,nR,nS,lambda,ERI,OmRPA,rho_RPA,B_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) :: eta
|
|
double precision,intent(in) :: lambda
|
|
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
|
|
double precision,intent(in) :: OmRPA(nS)
|
|
double precision,intent(in) :: rho_RPA(nBas,nBas,nS)
|
|
|
|
! Local variables
|
|
|
|
double precision :: chi
|
|
double precision :: eps
|
|
integer :: i,j,a,b,ia,jb,kc
|
|
|
|
! Output variables
|
|
|
|
double precision,intent(out) :: B_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
|
|
eps = OmRPA(kc)**2 + eta**2
|
|
! chi = chi + lambda*rho_RPA(i,b,kc)*rho_RPA(a,j,kc)*OmRPA(kc)/eps
|
|
chi = chi + rho_RPA(i,b,kc)*rho_RPA(a,j,kc)*OmRPA(kc)/eps
|
|
enddo
|
|
|
|
B_lr(ia,jb) = B_lr(ia,jb) - lambda*ERI(i,j,b,a) + 4d0*lambda*chi
|
|
|
|
enddo
|
|
enddo
|
|
enddo
|
|
enddo
|
|
|
|
end subroutine Bethe_Salpeter_B_matrix
|