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| vibration_correlation_programs [2024/11/13 10:14] – rauhut | vibration_correlation_programs [2025/01/24 15:14] (current) – rauhut |
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| T. Mathea, G. Rauhut, //Advances in vibrational configuration interaction theory - part 1: Efficient calculation of vibrational angular momentum terms.// [[https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.26762|J. Comput. Chem.]] **42**, 2321–2333 (2021).\\ | T. Mathea, G. Rauhut, //Advances in vibrational configuration interaction theory - part 1: Efficient calculation of vibrational angular momentum terms.// [[https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.26762|J. Comput. Chem.]] **42**, 2321–2333 (2021).\\ |
| T. Mathea, T. Petrenko, G. Rauhut, //Advances in vibrational configuration interaction theory - part 2: Fast screening of the correlation space.//. [[https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.26764|J. Comput. Chem.]] **43**, 6–18 (2022).\\ | T. Mathea, T. Petrenko, G. Rauhut, //Advances in vibrational configuration interaction theory - part 2: Fast screening of the correlation space.//. [[https://onlinelibrary.wiley.com/doi/abs/10.1002/jcc.26764|J. Comput. Chem.]] **43**, 6–18 (2022).\\ |
| B. Schröder, G. Rauhut, //From the automated calculation of potential energy surfaces to accurate vibrational spectra//, [[https://doi.org/10.1021/acs.jpclett.4c00186|J. Chem. Chem. Lett.]] **15**, 3159 (2024).\\ | B. Schröder, G. Rauhut, //From the automated calculation of potential energy surfaces to accurate vibrational spectra//, [[https://doi.org/10.1021/acs.jpclett.4c00186|J. Phys. Chem. Lett.]] **15**, 3159 (2024).\\ |
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| * **''PRINT''=//n//** This option provides an extended output. ''PRINT=1'' prints the vibrationally averaged rotational constants for all computed states and the associated vibration-rotation constants α. ''PRINT=2'' prints the effective 1D polynomials in case that the potential is represented in terms of polynomials, see the option ''POT=POLY'' and the ''POLY'' program. In addition the generalized VSCF property integrals, i.e. ⟨VSCF|qri|VSCF⟩ are printed. These integrals allow for the calculation of arbitrary vibrationally averaged properties once the property surfaces are available. Default: ''PRINT=0''. | * **''PRINT''=//n//** This option provides an extended output. ''PRINT=1'' prints the vibrationally averaged rotational constants for all computed states and the associated vibration-rotation constants α. ''PRINT=2'' prints the effective 1D polynomials in case that the potential is represented in terms of polynomials, see the option ''POT=POLY'' and the ''POLY'' program. In addition the generalized VSCF property integrals, i.e. ⟨VSCF|qri|VSCF⟩ are printed. These integrals allow for the calculation of arbitrary vibrationally averaged properties once the property surfaces are available. Default: ''PRINT=0''. |
| * **''REFERENCE''=//n//** This keyword specifies the reference for the definition of the configurations. By default, ''REFERENCE=0'' the reference for all state-specific calculations is the vibrational ground-state configuration. This leads to a violation of the Brillouin condition, but often to also to faster convergence. ''REFERENCE=1'' uses the VSCF configuration as reference for generating all excited configurations. This is the proper way of doing it, but usually requests higher excitation levels. | * **''REFERENCE''=//n//** This keyword specifies the reference for the definition of the configurations. By default, ''REFERENCE=0'' the reference for all state-specific calculations is the vibrational ground-state configuration. This leads to a violation of the Brillouin condition, but often to also to faster convergence. ''REFERENCE=1'' uses the VSCF configuration as reference for generating all excited configurations. This is the proper way of doing it, but usually requests higher excitation levels. |
| * **''SADDLE''=//n//** By default, i.e. ''SADDLE=0'', the ''VCI'' program assumes, that the reference point of the potential belongs to a local minimum. Once the PES calculation has been started from a transition state, this information must be provided to the ''VCI'' program by using ''SADDLE=1''. Currently, the ''VCI'' program can only handle symmetrical double-minimum potentials. | <!-- |
| | * **''SADDLE''=//n//** By default, i.e. ''SADDLE=0'', the ''VCI'' program assumes, that the reference point of the potential belongs to a local minimum. Once the PES calculation has been started from a transition state, this information must be provided to the ''VCI'' program by using ''SADDLE=1''. Currently, the ''VCI'' program can only handle symmetrical double-minimum potentials. --> |
| * **''SELSCHEME''=//n//** By default ''SELSCHEME''=1, configurationis will be selected by a perturbative criterion. Alternative one may use a criterion based on 2×2 VCI matrices (''SELSCHEME''=2). Usually the differences are extremely small and the matrix based criterion is slightly more time-consuming. | * **''SELSCHEME''=//n//** By default ''SELSCHEME''=1, configurationis will be selected by a perturbative criterion. Alternative one may use a criterion based on 2×2 VCI matrices (''SELSCHEME''=2). Usually the differences are extremely small and the matrix based criterion is slightly more time-consuming. |
| * **''SKIPDIAG''=//n//** If ''SKIPDIAG=//n//'' with //n//>1 is set (default: 2), the configuration selection based on a VMP2-like wavefunction is used after the //n//th iteration step, as long as the energy difference between the energy eigenvalues of the last two iteration steps is less than ''THRDIAG'' (see below). ''SKIPDIAG=2'' usually leads to appropriate results. | * **''SKIPDIAG''=//n//** If ''SKIPDIAG=//n//'' with //n//>1 is set (default: 2), the configuration selection based on a VMP2-like wavefunction is used after the //n//th iteration step, as long as the energy difference between the energy eigenvalues of the last two iteration steps is less than ''THRDIAG'' (see below). ''SKIPDIAG=2'' usually leads to appropriate results. |
| * **''THRUP''=//value//** Within the perturbative selection criterion, unselected configurations are excluded from the procedure based on a criterion, which checks on the selection of configuration, which are excited in the same modes. The default is ''THRUP''=10−9. | * **''THRUP''=//value//** Within the perturbative selection criterion, unselected configurations are excluded from the procedure based on a criterion, which checks on the selection of configuration, which are excited in the same modes. The default is ''THRUP''=10−9. |
| * **''VAM''=//n//** ''VAM=0'': switches off all vibrational angular momentum terms and the Watson correction term.\\ | * **''VAM''=//n//** ''VAM=0'': switches off all vibrational angular momentum terms and the Watson correction term.\\ |
| * ''VAM=1'': adds the Watson correction term (see eq. [[#eq:1|[eq:1]]]) as a pseudo-potential like contribution to the fine grid of the potential. In the analytical representation of the potential this will already be done in the ''POLY'' program.\\ | * ''VAM=1'': adds the Watson correction term as a pseudo-potential like contribution to the fine grid of the potential. In the analytical representation of the potential this will already be done in the ''POLY'' program.\\ |
| * ''VAM=2'': the 0D terms of the vibrational angular momentum terms, i.e. 12∑αβˆπαμαβˆπβ, and the Watson correction term are included. The VAM-terms will be added to the diagonal elements of the VCI-matrix only. This approximations works rather well for many applications.\\ | * ''VAM=2'': the 0D terms of the vibrational angular momentum terms, i.e. 12∑αβˆπαμαβˆπβ, and the Watson correction term are included. The VAM-terms will be added to the diagonal elements of the VCI-matrix only. This approximations works rather well for many applications.\\ |
| * ''VAM=3'': (default) the μ tensor is given as the inverse of the moment of inertia tensor at equilibrium geometry, but is added to all elements of the VCI matrix.\\ | * ''VAM=3'': (default) the μ tensor is given as the inverse of the moment of inertia tensor at equilibrium geometry, i.e. the 0th order term of the μ-tensor expansion, but it is added to all elements of the VCI matrix.\\ |
| * ''VAM=4'': extends the constant μ-tensor (0D) by 1D terms. The 1D VAM-terms will be added to the diagonal elements of the VCI-matrix only. \\ | * ''VAM=4'': extends the constant μ-tensor (0D) by 1D terms. The 1D VAM-terms will be added to the diagonal elements of the VCI-matrix only. \\ |
| * ''VAM=5'': includes 0D and 1D μ-tensor, which are added to all elements of the VCI matrix. Prescreening is used for the 1D terms.\\ | * ''VAM=5'': includes 0D and 1D μ-tensor, which are added to all elements of the VCI matrix. Prescreening is used for the 1D terms.\\ |
| * **''DUMP_RAMAN''=//string//** File name for dumping the rovibrational Raman line list. Activates calculation of rovibrational intensities. | * **''DUMP_RAMAN''=//string//** File name for dumping the rovibrational Raman line list. Activates calculation of rovibrational intensities. |
| * **''HOTB''=//n//** (=0 (off) Default) The calculation of vibrational hot bands can be switched on with ''HOTB=1''. | * **''HOTB''=//n//** (=0 (off) Default) The calculation of vibrational hot bands can be switched on with ''HOTB=1''. |
| * **''THRESHOLD_HOTB''=//n//** (=5d-2 Default) Minimum of the relative thermal occupation for the lower vibrational mode, in order to be considered as a hot band. | |
| * **''INFO''=//n//** (=1 Default) Additional rovibrational output. By default this will print the nuclear spin statistical weights. ''INFO=2'' provides additional details on the calculation and assignment of nuclear spin statstical weights. ''INFO=3'' enables further integrals, etc. | * **''INFO''=//n//** (=1 Default) Additional rovibrational output. By default this will print the nuclear spin statistical weights. ''INFO=2'' provides additional details on the calculation and assignment of nuclear spin statstical weights. ''INFO=3'' enables further integrals, etc. |
| * **''IRUNIT''=//string//** The default unit for the IR intensities in HITRAN units, i.e. cm−1/(molecule cm−2). Alternatively, one may use ''IRUNIT=KMMOL'' to specify km/mol. | * **''IRUNIT''=//string//** The default unit for the IR intensities in HITRAN units, i.e. cm−1/(molecule cm−2). Alternatively, one may use ''IRUNIT=KMMOL'' to specify km/mol. |
| * **''JMAX''=//n//** By default VCI calculations will be performed for non-rotating molecules, i.e. ''J=0''. Rovibrational levels can be computed for arbitrary numbers of ''J=n''. This will perform a purely rotational calculation (RCI). To obtain approximate rovibrational energies, vibrational energies have to be added. | * **''JMAX''=//n//** By default VCI calculations will be performed for non-rotating molecules, i.e. ''J=0''. Rovibrational levels can be computed for arbitrary numbers of ''J=n''. This will perform a purely rotational calculation (RCI). To obtain approximate rovibrational energies, vibrational energies have to be added. |
| * **''LLPRINT''=//n//** This keyword controls the rovibrational line list printout. ''LLPRINT=1'' prints the transition moments, ''LLPRINT=2'' the oscillator strengths, ''LLPRINT=3'' the Einstein A coefficients, ''LLPRINT=4'' symmetry information, and ''LLPRINT=5'' vibrational hot bands. Any of these numbers can be combined, e.g. ''LLPRINT=123'' prints the transition moments, the oscillator strengths and the Einstein A coefficients. This keyword or the ''DUMP_IR'' and/or ''DUMP_RAMAN'' keyword have to be set in order to compute rovibrational intensitites. | |
| * **''JMAX_PRINT''=//n//** (=3 Default for ''JMAX''>3) This option controls the printout in rovibrational calculations, i.e. the maximum J value, up to which information shall be printed. | * **''JMAX_PRINT''=//n//** (=3 Default for ''JMAX''>3) This option controls the printout in rovibrational calculations, i.e. the maximum J value, up to which information shall be printed. |
| | * **''LLPRINT''=//n//** This keyword controls the rovibrational line list printout. ''LLPRINT=1'' prints the transition moments, ''LLPRINT=2'' symmetry information, ''LLPRINT=3'' the Einstein A coefficients, ''LLPRINT=4'' the oscillator strength, and ''LLPRINT=5'' vibrational hot bands. Any of these numbers can be combined, e.g. ''LLPRINT=123'' prints the transition moments, symmetry information and the Einstein A coefficients. This keyword or the ''DUMP_IR'' and/or ''DUMP_RAMAN'' keyword have to be set in order to compute rovibrational intensitites. |
| * **''NDIMCOR''=//n//** (=2) Order of the μ-tensor expansion within Coriolis coupling terms. ''NDIMCOR=0'' denotes no Coriolis coupling. ''NDIMCOR=1'' considers 0th order terms, ''NDIMCOR=2'' uses 1st order term, ''NDIMCOR=3'' is the highest implemented value and uses 2nd order terms. | * **''NDIMCOR''=//n//** (=2) Order of the μ-tensor expansion within Coriolis coupling terms. ''NDIMCOR=0'' denotes no Coriolis coupling. ''NDIMCOR=1'' considers 0th order terms, ''NDIMCOR=2'' uses 1st order term, ''NDIMCOR=3'' is the highest implemented value and uses 2nd order terms. |
| * **''NDIMDIP''=//n//** (Default is identical to previous VCI calculation) Order of the n-mode expansion of the dipole surfaces used for the calculation of the vibrational transition moments in rovibrational intensities. | * **''NDIMDIP''=//n//** (Default is identical to previous VCI calculation) Order of the n-mode expansion of the dipole surfaces used for the calculation of the vibrational transition moments in rovibrational intensities. |
| * **''NDIMPOL''=//n//** (Default is identical to previous VCI calculation) Order of the n-mode expansion of the polarizability surfaces used for the calculation of the vibrational transition moments in rovibrational intensities. | * **''NDIMPOL''=//n//** (Default is identical to previous VCI calculation) Order of the n-mode expansion of the polarizability surfaces used for the calculation of the vibrational transition moments in rovibrational intensities. |
| * **''NDIMROT''=//n//** (=3) Order of the μ-tensor expansion within rotational terms. ''NDIMROT=1'' considers 0th order terms, ''NDIMROT=2'' uses 1st order terms up to ''NDIMROT=4'' for 3rd order terms. | * **''NDIMROT''=//n//** (=3) Order of the μ-tensor expansion within rotational terms. ''NDIMROT=1'' considers 0th order terms, ''NDIMROT=2'' uses 1st order terms up to ''NDIMROT=4'' for 3rd order terms. |
| | * **''NSSW''=//'i-j-k...'//** The nuclear spin statistical weights will be determined automatically. However, the can also be provided explicitly by this keyword. The number of NSSWs must match the number of irreps and the different NSSWs need to be separated by minus signs. |
| * **''PARTF''=//0,1,2//** (= 1 Default) Mode rovibrational partition function. If equals ''0'', then partition function gets not calculated. For ''PARTF=1'' partition function is calculated with separation approximation and for ''PARTF=2'' only all RVCI energies are used. | * **''PARTF''=//0,1,2//** (= 1 Default) Mode rovibrational partition function. If equals ''0'', then partition function gets not calculated. For ''PARTF=1'' partition function is calculated with separation approximation and for ''PARTF=2'' only all RVCI energies are used. |
| * **''PARTF_R_THR''=//value//** (=10−4 Default) Threshold for the relative deviation within the iterative determination of the rotational partition function. | |
| * **''PARTF_V_THR''=//value//** (=10−4 Default) Threshold for the relative deviation within the iterative determination of the vibrational partition function. | |
| * **''PFIT''=//value//** (=0 Default) Fitting of spectroscopic parameters for asymmetric tops using Watson's reduced operator. ''PFIT=1'' activates the fitting procedure if ''JMAX>0''. IR Intensities are not needed for the fitting! By setting ''PFIT=2'' additional printout of the optimization algorithm is provided. | * **''PFIT''=//value//** (=0 Default) Fitting of spectroscopic parameters for asymmetric tops using Watson's reduced operator. ''PFIT=1'' activates the fitting procedure if ''JMAX>0''. IR Intensities are not needed for the fitting! By setting ''PFIT=2'' additional printout of the optimization algorithm is provided. |
| * **''PFITCUT''=//0,1//** (=0 Default) By default, the whole reference data set is used by PFIT. Setting this keyword to (1) will activate a filter that cuts data points with a high residuum from the data set and improves overall convergence slightly. | * **''PFITCUT''=//0,1//** (=0 Default) By default, the whole reference data set is used by PFIT. Setting this keyword to (1) will activate a filter that cuts data points with a high residuum from the data set and improves overall convergence slightly. |
| * ''RBAS=4'' uses a molecule specific rotational basis (MSRB) generated from a linear combination of Wang combinations. | * ''RBAS=4'' uses a molecule specific rotational basis (MSRB) generated from a linear combination of Wang combinations. |
| * ''RBAS=5'' symmetrized Wang combinations are used, i.e. |JKτ>=iτ(−1)σ/√2(|JK>+(−1)J+K+τ|J−K>), which results in a real-valued RVCI matrix, while all other bases lead to a complex RVCI matrix. | * ''RBAS=5'' symmetrized Wang combinations are used, i.e. |JKτ>=iτ(−1)σ/√2(|JK>+(−1)J+K+τ|J−K>), which results in a real-valued RVCI matrix, while all other bases lead to a complex RVCI matrix. |
| * **''RVINTTHR''=//value//** (=10−6 Default) Threshold for printing rovibrational lines relative to the intensity of the strongest line. | |
| * **''RAMAN_POLANG''=//value//** (=90 Default) Raman polarization angle defining the prefactors mixing the isotropic and anisotropic Raman transition moments for the calculation of Raman intensities. | * **''RAMAN_POLANG''=//value//** (=90 Default) Raman polarization angle defining the prefactors mixing the isotropic and anisotropic Raman transition moments for the calculation of Raman intensities. |
| * **''RAMAN_FAC(n)''=//value//** Set the prefactors for the isotropic and anisotropic Raman transition moments for the calculation of Raman intensities manually. n=0 will set the value for R0, n=2 the one for R2. | * **''RAMAN_FAC(n)''=//value//** Set the prefactors for the isotropic and anisotropic Raman transition moments for the calculation of Raman intensities manually. n=0 will set the value for R0, n=2 the one for R2. |
| * **''RAMAN_LFREQ''=//value//** (=680 Default, in nm) Raman exciting radiation (laser) frequency. | * **''RAMAN_LFREQ''=//value//** (=680 Default, in nm) Raman exciting radiation (laser) frequency. |
| * **''SPARSITY''=//0,1//** (=1 (on) Default) allows to use sparsity within the storage of the RVCI eigenvectors, which also accelerates the calculation of the infrared intensities. | * **''SPARSITY''=//0,1//** (=1 (on) Default) allows to use sparsity within the storage of the RVCI eigenvectors, which also accelerates the calculation of the infrared intensities. |
| * **''SPARSTHR''=//n//** (=5 Default) general sparsity threshold for RVCI eigenvectors. n refers to the actual threshold of 10−n/(J+1) with J being the rotational quantum number. | |
| * **''SYM''=//0,1//** (=1 (on) Default) Abelian point group symmetry is exploited within the construction of the RVCI matrix. | * **''SYM''=//0,1//** (=1 (on) Default) Abelian point group symmetry is exploited within the construction of the RVCI matrix. |
| * **''TEMP''=//value//** (=300 Default, in Kelvin) Spectra for different temperatures can be calculated during plotting using the temperature dependent thermal occupation prefactor and the corresponding partition function value. But a maximum temperature is needed for the calculation to define the highest occupied states. This temperature is set by this parameter. | * **''TEMP''=//value//** (=300 Default, in Kelvin) Spectra for a given temperature can be calculated using the temperature dependent thermal occupation prefactor and the corresponding partition function value. |
| | * **''THRHOTB''=//n//** (=5d-2 Default) Minimum of the relative thermal occupation for the lower vibrational mode, in order to be considered as a hot band. |
| | * **''THRROTPF''=//value//** (=10−4 Default) Threshold for the relative deviation within the iterative determination of the rotational partition function. |
| | * **''THRRVINT''=//value//** (=10−6 Default) Threshold for printing rovibrational lines relative to the intensity of the strongest line. |
| | * **''THRSPARS''=//n//** (=5 Default) general sparsity threshold for RVCI eigenvectors. n refers to the actual threshold of 10−n/(J+1) with J being the rotational quantum number. |
| | * **''THRVIBPF''=//value//** (=10−4 Default) Threshold for the relative deviation within the iterative determination of the vibrational partition function. |
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| ==== Explicit definition of the correlation space ==== | ==== Explicit definition of the correlation space ==== |
| * **''SAVE''=//record//** This keyword specifies the record where to dump the VCI information. | * **''SAVE''=//record//** This keyword specifies the record where to dump the VCI information. |
| * **''START''=//record//** This card specifies the record from where to read the VSCF information. As the VSCF information usually is stored in the same record as the polynomials, it is usually defined in the ''POLY'' program. | * **''START''=//record//** This card specifies the record from where to read the VSCF information. As the VSCF information usually is stored in the same record as the polynomials, it is usually defined in the ''POLY'' program. |
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| ===== The vibrational Møller-Plesset programs (VMP2, VMP3, VMP4) ===== | ===== The vibrational Møller-Plesset programs (VMP2, VMP3, VMP4) ===== |
| ''VMPx'',//options// | ''VMPx'',//options// |
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| The ''VMPx'' (x=2,3,4) programs allow to perform 2nd to 4th order vibrational Møller-Plesset calculations. 3rd and 4th order perturbation theory is only available for polynomial based PESs. Most of the keywords as described for the ''VCI'' program are also valid for these perturbational programs, i.e. ''%%CITYPE, LEVEX, CIMAX, NDIM, VAM, MPG%%'' and ''INFO''. | The ''VMPx'' (x=2,3,4) programs allow to perform 2nd to 4th order vibrational Møller-Plesset calculations. 3rd and 4th order perturbation theory is only available for polynomial based PESs. Any properties (except energies) will always be computed at the level of VMP2. Most of the keywords as described for the ''VCI'' program are also valid for these perturbational programs, i.e. ''%%CITYPE, LEVEX, CIMAX, NDIM, VAM, MPG%%'' and ''INFO''. |
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| The following //additional options// are available: | The following //additional options// are available: |