mirror of
https://github.com/pfloos/quack
synced 2024-07-05 10:56:01 +02:00
61 lines
1.3 KiB
Fortran
61 lines
1.3 KiB
Fortran
subroutine linear_response_C_pp(ispin,dRPA,nBas,nC,nO,nV,nR,nOO,nVV,e,ERI,C_pp)
|
|
|
|
! Compute the C matrix of the pp channel
|
|
|
|
implicit none
|
|
include 'parameters.h'
|
|
|
|
! Input variables
|
|
|
|
integer,intent(in) :: ispin
|
|
logical,intent(in) :: dRPA
|
|
integer,intent(in) :: nBas,nC,nO,nV,nR,nOO,nVV
|
|
double precision,intent(in) :: e(nBas),ERI(nBas,nBas,nBas,nBas)
|
|
|
|
! Local variables
|
|
|
|
double precision :: delta_spin
|
|
double precision :: delta_dRPA
|
|
double precision :: eF
|
|
double precision,external :: Kronecker_delta
|
|
|
|
integer :: a,b,c,d,ab,cd
|
|
|
|
! Output variables
|
|
|
|
double precision,intent(out) :: C_pp(nVV,nVV)
|
|
|
|
! 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 C matrix
|
|
|
|
eF = e(nO) + e(nO+1)
|
|
|
|
ab = 0
|
|
do a=nO+1,nBas-nR
|
|
do b=a+1,nBas-nR
|
|
ab = ab + 1
|
|
cd = 0
|
|
do c=nO+1,nBas-nR
|
|
do d=c+1,nBas-nR
|
|
cd = cd + 1
|
|
|
|
C_pp(ab,cd) = + (e(a) + e(b) - eF)*Kronecker_delta(a,c)*Kronecker_delta(b,d) &
|
|
+ (1d0 + delta_spin)*ERI(a,b,c,d) - (1d0 - delta_dRPA)*ERI(a,b,d,c)
|
|
|
|
enddo
|
|
enddo
|
|
enddo
|
|
enddo
|
|
|
|
end subroutine linear_response_C_pp
|