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37 lines
1.1 KiB
Fortran
37 lines
1.1 KiB
Fortran
BEGIN_PROVIDER [double precision, two_e_dm_mo, (mo_num,mo_num,mo_num,mo_num)]
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implicit none
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BEGIN_DOC
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! \sum_{\sigma \sigma'}
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! <Psi| a^{\dagger}_{i \sigma} a^{\dagger}_{j \sigma'} a_{l \sigma'} a_{k \sigma} |Psi>
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!
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! where the indices (i,j,k,l) belong to all MOs.
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!
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! The normalization (i.e. sum of diagonal elements) is set to $N_{elec} * (N_{elec} - 1)/2$
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!
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! !!!!! WARNING !!!!! IF "no_core_density" then all elements involving at least one CORE MO are set to zero
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! The state-averaged two-electron energy :
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!
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! \sum_{i,j,k,l = 1, mo_num} two_e_dm_mo(i,j,k,l) * < kk ll | ii jj >
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END_DOC
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two_e_dm_mo = 0.d0
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integer :: i,j,k,l,iorb,jorb,korb,lorb,istate
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do l=1,mo_num
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lorb = list_core_inact_act(l)
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do k=1,mo_num
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korb = list_core_inact_act(k)
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do j=1,mo_num
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jorb = list_core_inact_act(j)
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do i=1,mo_num
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iorb = list_core_inact_act(i)
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two_e_dm_mo(iorb,jorb,korb,lorb) = state_av_full_occ_2_rdm_spin_trace_mo(i,j,k,l)
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enddo
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enddo
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enddo
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enddo
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two_e_dm_mo(:,:,:,:) = two_e_dm_mo(:,:,:,:)
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! * 2.d0
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END_PROVIDER
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