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| automated_construction_of_atomic_valence_active_spaces [2025/09/03 11:19] – cosmetic doll | automated_construction_of_atomic_valence_active_spaces [2026/01/30 13:54] (current) – doll |
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| where //n// is the principal quantum number, and //type// is ''%%s, p, d%%'',…. Alternatively, individual components such as ''%%px, py, pz%%'', or ''%%d0, d1+, d1-, d2+, d2-%%'' can also be given, and then only the specified functions are used (otherwise all components are included). If the principal quantum number $n$ is given, the $n-l$’th atomic function of the given type will be used (e.g., for ''2s'' the second $s$-function, for ''2p'', the first $p$ function, for ''4d'' the second $d$ function). If $n$ is not given, the first function of the given type is used. | where //n// is the principal quantum number, and //type// is ''%%s, p, d%%'',…. Alternatively, individual components such as ''%%px, py, pz%%'', or ''%%d0, d1+, d1-, d2+, d2-%%'' can also be given, and then only the specified functions are used (otherwise all components are included). If the principal quantum number $n$ is given, the $n-l$’th atomic function of the given type will be used (e.g., for ''2s'' the second $s$-function, for ''2p'', the first $p$ function, for ''4d'' the second $d$ function). If $n$ is not given, the first function of the given type is used. |
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| From Molpro version 2022.2 $n$ is the principal quantum number, independent of how many orbitals are in peudopotentials (ECPs). This is different to earlier versions, were $n$ counted the number of orbitals outside the ECP. | From Molpro version 2022.2 $n$ is the principal quantum number, independent of how many orbitals are in pseudopotentials (ECPs). This is different to earlier versions, were $n$ counted the number of orbitals outside the ECP. |
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| Example: | Example: |
| * **''MINAO_BASIS''=//name//** Minimal atomic basis set (default ''MINAO'') The specified basis set should be generally contracted, so that the first CGTOs for each angular momentum correspond to the atomic core and valence orbitals. If non-valence orbitals are requested (e.g. 4d for first-row transition metals) the basis must contain at least two CGTOs of the corresponding angular momentum. In this case the default MINAO would is not sufficient and a larger basis must be specified, e.g., VTZ (or, equivalently, cc-pVTZ). | * **''MINAO_BASIS''=//name//** Minimal atomic basis set (default ''MINAO'') The specified basis set should be generally contracted, so that the first CGTOs for each angular momentum correspond to the atomic core and valence orbitals. If non-valence orbitals are requested (e.g. 4d for first-row transition metals) the basis must contain at least two CGTOs of the corresponding angular momentum. In this case the default MINAO would is not sufficient and a larger basis must be specified, e.g., VTZ (or, equivalently, cc-pVTZ). |
| * **''CORE=''//val//** If ''CORE=1'' core orbitals are included in the projection (default: ''CORE=0'') | * **''CORE=''//val//** If ''CORE=1'' core orbitals are included in the projection (default: ''CORE=0'') |
| * **''OPEN=''//val//** If ''OPEN=1'' closed-shell and open-shell orbitals are included together in the projection (default: ''OPEN=0'' if called from RHF, ''OPEN=1'' if called using the ''AVAS'' command). ''OPEN=1'' will not keep the ROHF energy invariant. | * **''OPEN=''//val//** If ''OPEN=1'' closed-shell and open-shell orbitals are included together in the projection (default: ''OPEN=0'' if called from RHF, ''OPEN=1'' if called using the ''AVAS'' command). ''OPEN=1'' will not keep the open-shell RHF energy invariant. |
| * **''VIRT=''//val//** If ''VIRT=0'' virtual orbitals are not projected (default: ''VIRT=1'') | * **''VIRT=''//val//** If ''VIRT=0'' virtual orbitals are not projected (default: ''VIRT=1'') |
| * **''NELA=''//val//** Number of active electrons. If ''OCC'' and ''CLOSED'' are not given, this determines the number of closed-shell orbitals. | * **''NELA=''//val//** Number of active electrons. If ''OCC'' and ''CLOSED'' are not given, this determines the number of closed-shell orbitals. |
| A subsequent CASSCF (MULTI) calculation will automatically use the generated active space (unless specified otherwise) and use the AVAS orbitals (unless different orbitals are specified on a ''START'' directive). | A subsequent CASSCF (MULTI) calculation will automatically use the generated active space (unless specified otherwise) and use the AVAS orbitals (unless different orbitals are specified on a ''START'' directive). |
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| It is recommended to first do a CASSCI calculation using | It is recommended to first do a CASCI calculation using |
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| <code> | <code> |
| ====== AVAS within HF or KS ====== | ====== AVAS within HF or KS ====== |
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| In this case the converged HF orbitals are used, and the closed-shell valence orbitals (excluding core orbitals) and virtual orbitals are projected independently, and the active orbitals resulting from these two subspaces are determined. IF ''OPEN=0'' (default in this case) the open-shell orbitals remain unchanged and are subsequently added to the active space. In this way, a CASSCI using the generated active space will never give a higher energy than the RHF energy, and according to preliminary experience this yields the best starting orbitals for a subsequent CASSCF calculation. The inactive, active and virtual subspaces are made pseudo-canonical by block-diagonalizing the Fock matrix. | In this case the converged HF orbitals are used, and the closed-shell valence orbitals (excluding core orbitals) and virtual orbitals are projected independently, and the active orbitals resulting from these two subspaces are determined. IF ''OPEN=0'' (default in this case) the open-shell orbitals remain unchanged and are subsequently added to the active space. In this way, a CASCI using the generated active space will never give a higher energy than the RHF energy, and according to preliminary experience this yields the best starting orbitals for a subsequent CASSCF calculation. The inactive, active and virtual subspaces are made pseudo-canonical by block-diagonalizing the Fock matrix. |
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| The general input is | The general input is |