mirror of https://github.com/pfloos/quack
36 lines
792 B
Fortran
36 lines
792 B
Fortran
subroutine spatial_to_spin_ERI(nBas,ERI,nBas2,sERI)
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! Convert ERIs from spatial to spin orbitals
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implicit none
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! Input variables
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integer,intent(in) :: nBas,nBas2
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double precision,intent(in) :: ERI(nBas,nBas,nBas,nBas)
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! Local variables
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integer :: p,q,r,s
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double precision,external :: Kronecker_delta
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! Output variables
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double precision,intent(out) :: sERI(nBas2,nBas2,nBas2,nBas2)
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do p=1,nBas2
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do q=1,nBas2
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do r=1,nBas2
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do s=1,nBas2
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sERI(p,q,r,s) = Kronecker_delta(mod(p,2),mod(r,2)) &
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* Kronecker_delta(mod(q,2),mod(s,2)) &
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* ERI((p+1)/2,(q+1)/2,(r+1)/2,(s+1)/2)
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end do
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end do
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end do
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end do
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end subroutine
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