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QuAcK/src/eDFT/restricted_fock_exchange_potential.f90

37 lines
723 B
Fortran

subroutine restricted_fock_exchange_potential(nBas,P,ERI,Fx)
! Compute the Fock exchange potential
implicit none
! Input variables
integer,intent(in) :: nBas
double precision,intent(in) :: P(nBas,nBas)
double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
! Local variables
integer :: mu,nu,la,si
! Output variables
double precision,intent(out) :: Fx(nBas,nBas)
! Compute HF exchange matrix
Fx(:,:) = 0d0
do si=1,nBas
do la=1,nBas
do nu=1,nBas
do mu=1,nBas
Fx(mu,nu) = Fx(mu,nu) - P(la,si)*ERI(mu,la,si,nu)
enddo
enddo
enddo
enddo
Fx(:,:) = 0.5d0*Fx(:,:)
end subroutine restricted_fock_exchange_potential