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41 lines
1.5 KiB
Fortran
41 lines
1.5 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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! two_e_dm_bb_mo(i,j,k,l,istate) = STATE SPECIFIC physicist notation for 2RDM of beta/beta electrons
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!
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! <Psi| a^{\dagger}_{i \beta} a^{\dagger}_{j \beta} a_{l \beta} a_{k \beta} |Psi>
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!
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! WHERE ALL ORBITALS (i,j,k,l) BELONGS TO ALL OCCUPIED ORBITALS : core, inactive and active
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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 !!!!! ALL SLATER DETERMINANTS IN PSI_DET MUST BELONG TO AN ACTIVE SPACE DEFINED BY "list_act"
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!
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! !!!!! WARNING !!!!! IF "no_core_density" then all elements involving at least one CORE MO is set to zero
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! The two-electron energy of each state can be computed as:
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!
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! \sum_{i,j,k,l = 1, n_core_inact_act_orb} two_e_dm_mo(i,j,k,l,istate) * < ii jj | kk ll >
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!
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! with ii = list_core_inact_act(i), jj = list_core_inact_act(j), kk = list_core_inact_act(k), ll = list_core_inact_act(l)
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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(:,:,:,:) * 2.d0
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END_PROVIDER
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