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quantum_package/plugins/MRPT_Utils/give_2h2p.irp.f
2016-11-30 17:02:28 +01:00

36 lines
1.2 KiB
Fortran

subroutine give_2h2p(contrib_2h2p)
implicit none
double precision, intent(out) :: contrib_2h2p(N_states)
integer :: i,j,k,l,m
integer :: iorb,jorb,korb,lorb
double precision :: get_mo_bielec_integral
double precision :: direct_int,exchange_int
double precision :: numerator,denominator(N_states)
contrib_2h2p = 0.d0
do i = 1, n_inact_orb
iorb = list_inact(i)
do j = 1, n_inact_orb
jorb = list_inact(j)
do k = 1, n_virt_orb
korb = list_virt(k)
do l = 1, n_virt_orb
lorb = list_virt(l)
direct_int = get_mo_bielec_integral(iorb,jorb,korb,lorb ,mo_integrals_map)
exchange_int = get_mo_bielec_integral(iorb,jorb,lorb,korb ,mo_integrals_map)
numerator = 3.d0 * direct_int*direct_int + exchange_int*exchange_int -2.d0 * exchange_int * direct_int
do m = 1, N_states
denominator(m) = fock_core_inactive_total_spin_trace(iorb,m) + fock_core_inactive_total_spin_trace(jorb,m) &
-fock_virt_total_spin_trace(korb,m) - fock_virt_total_spin_trace(lorb,m)
contrib_2h2p(m) += numerator / denominator(m)
enddo
enddo
enddo
enddo
enddo
contrib_2h2p = contrib_2h2p*0.5d0
end