mirror of
https://github.com/pfloos/quack
synced 2024-10-18 14:01:49 +02:00
57 lines
1.2 KiB
Fortran
57 lines
1.2 KiB
Fortran
|
subroutine linear_response_A_matrix(ispin,dRPA,nBas,nC,nO,nV,nR,nS,e,ERI,A_lr)
|
||
|
|
||
|
! Compute linear response
|
||
|
|
||
|
implicit none
|
||
|
include 'parameters.h'
|
||
|
|
||
|
! Input variables
|
||
|
|
||
|
logical,intent(in) :: dRPA
|
||
|
integer,intent(in) :: ispin,nBas,nC,nO,nV,nR,nS
|
||
|
double precision,intent(in) :: e(nBas),ERI(nBas,nBas,nBas,nBas)
|
||
|
|
||
|
! Local variables
|
||
|
|
||
|
double precision :: delta_spin,delta_dRPA
|
||
|
double precision :: Kronecker_delta
|
||
|
|
||
|
integer :: i,j,a,b,ia,jb
|
||
|
|
||
|
! Output variables
|
||
|
|
||
|
double precision,intent(out) :: A_lr(nS,nS)
|
||
|
|
||
|
! Singlet or triplet manifold?
|
||
|
|
||
|
delta_spin = 0d0
|
||
|
if(ispin == 1) delta_spin = +1d0
|
||
|
if(ispin == 2) delta_spin = -1d0
|
||
|
|
||
|
! Direct RPA
|
||
|
|
||
|
delta_dRPA = 0d0
|
||
|
if(dRPA) delta_dRPA = 1d0
|
||
|
|
||
|
! Build A matrix
|
||
|
|
||
|
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
|
||
|
|
||
|
A_lr(ia,jb) = (e(a) - e(i))*Kronecker_delta(i,j)*Kronecker_delta(a,b) &
|
||
|
+ (1d0 + delta_spin)*ERI(i,b,a,j) &
|
||
|
- (1d0 - delta_dRPA)*ERI(i,b,j,a)
|
||
|
|
||
|
enddo
|
||
|
enddo
|
||
|
enddo
|
||
|
enddo
|
||
|
|
||
|
end subroutine linear_response_A_matrix
|