General: **PROPERTIES

 

This module controls the main features of the property calculation, that is, which properties is to be calculated. In addition it includes directives affecting the performance of several of the program sections. It should be noted, however, that the specification of what kind of walk (minimization , location of transition states , dynamical walks ) is given in the *WALK   or *MINIMI   submodules in the general input module. See also Chapter .

.ABALNR  

Invokes the calculation of frequency dependent linear response   calculations of operators. At present this only includes the frequency dependent polarizability  as well as directives controlling the calculation of Raman related properties   .

.CAVORG  

READ (LUCMD,*) (CAVORG(ICOOR), ICOOR = 1, 3)

Reads the origin to be used for the cavity   during a solvent calculation. By this default this is chosen to be the center of mass . Should by used with care, as it has to correspond to the center used in the evaluation of the undifferentiated solvent integrals in the HERMIT  section.

.DIPGRA  

Invokes the calculation of dipole moment gradients    (commonly known also as Atomic Polar Tensors (APTs)) as described in Ref. [80]. If combined with a request for .VIBANA   this will generate IR intensities .

.DIPORG  

READ (LUCMD, *) (DIPORG(ICOOR), ICOOR = 1, 3)

Reads in a user defined dipole origin . This may affect properties in which changes in dipole origin  is canceled by similar changes in the nuclear part. It should also be used with care, as the same dipole origin must be used during the integral evaluation sections , in particular if one is doing numerical differentiation with respect to electric field perturbations. For such finite-field calculations  we refer to Chapter , which deals with finite field calculations. It's use is mainly for debugging.

.ECD  

Invokes the calculation of Electronic Circular Dichroism (ECD)   as described in Ref. [49]. This necessitates the specification of the number electronic excitations  in each symmetry, given in the *EXCITA   module. The reader is refered to the section where the calculation of ECD is described in more detail (Sec. ).

.EXCITA   Invokes the calculation of electronic excitation   energies as residues of linear response functions   as described by Olsen and Jørgensen [28]. It also calculates closely related properties like transition moments   and rotatory strengths.

.EXPFCK  

Invokes the simultaneous calculation of two-electron expectation values and derivative Fock-matrices. This is default in direct and parallel runs in order to save memory. In ordinary calculations the total CPU time will increase as a result of invoking this option.

.GAUGEO  

READ (LUCMD, *) (GAGORG(ICOOR), ICOOR = 1, 3)

Reads in a user defined gauge origin  and overwrite both the .NOCMC   option, as well as the default value of center-of-mass coordinates. Not that an unsymmetric position of the gauge origin will lead to wrong results in calculations employing symmetry.

.INPTES  

Checks the input only and then stops.

.ISOTOP  

READ (LUCMD,*) NIS
READ (LUCMD, *) (ISOTOP(IS), IS = 1, NIS)

Read one more line indicating the number of nuclei for which the isotope will be explicitly given. On the next line read the isotope chosen for each nuclei .

By default the isotope chosen for each nucleus is the most abundant one. Although one may choose the number of nuclei for which an isotopic substitution is to be given explicitly, one should notice that this ordering follows the ordering of the atoms in the input. Thus, if only the last atom is to be an isotope different from the most common, all atoms has to be specified (and this applies to all nuclei, not only the symmetry independent one, se also Sec. ).

The ordering of the isotopes for each nuclei is in the order of natural abundance. Thus deuterium will be isotope 2 of hydrogen, while tritium will be isotope 3.

The choice of isotopic substituted molecules will affect the gauge origin , as well as dynamical walks  and walks using mass-weighted normal  modes, which depend on the choice of isotopic substitution. We notice that for the vibrational analysis , the isotopic substitution may be introduced rather late, there is a similar .ISOTOP  | keyword in the *VIBANA   input module. This can also be used to study the vibrational and rotational structure of several isotopic substituted species.

.MAGNET  

Invokes the calculation of the molecular magnetizability  (commonly known as magnetic susceptibility) as described in Ref. [31] and the rotational g tensor (see keyword .MOLGFA  ) . By default this is done using London orbitals  in order to ensure fast basis set convergence as shown in Ref. [31]. The use of London orbitals can be disabled by the keyword .NOLOND  .

Furthermore, the natural connection  (Ref. [34, 50]) is default in order to ensure numerically stable results. The natural connection can be turned off and instead use the symmetric connection  by the keyword .NODIFC  .

The gauge origin  are chosen to be the center of mass  of the molecule. This origin can be changed by the two keywords .GAUGEO   and .NOCMC  . This will of course not affect the total magnetizability, only the size of the dia- and paramagnetic terms.

.MOLGFA  

Invokes the calculation of the rotational g tensor  as described in Ref. [44] and the molecular magnetizability  (see keyword .MAGNET  ). By default this is done using London orbitals  and the natural connection . The use of London orbitals can be turned off by the keyword .NOLOND  .

By definition the gauge origin  of the molecular g-factor is to be the center of mass  of the molecule, and although the gauge origin can be changed through the keywords .NOCMC and .GAUGEO, this is not recommended, and may give erroneous results.

.MOLGRA  

Invokes the calculation of the analytical molecular gradient as  described in Ref. [7].

.MOLHES  

Invokes the calculation of the analytical molecular Hessian  and gradient  as described in Ref. [7].

.NACME  

Invokes the calculation of non-adiabatic coupling  matrix elements as described in Ref. [70]. Presently, complete non-adiabatic coupling matrix elements cannot be obtained from this keyword alone, but has to be combined with subsequent calculations in the RESPONSE  program. Currently inactive option.

.NMR  

Invokes the calculation of both parameters entering the NMR spin-Hamiltonian, that is nuclear shieldings  and indirect nuclear spin-spin coupling  constants. The reader is refered to the description of the to keywords .SHIELD   and .SPIN-S  .

.NOCMC  

This keyword sets the gauge origin  to be equal to the origin of the Cartesian Coordinate system, that is (0,0,0). This keyword is automatically invoked in case of VCD calculations.

.NODARW  

Turns off the calculation of the Darwin correction . By default the two relativistic corrections to the energy, the mass-velocity  and Darwin corrections, are calculated perturbatively.

.NODIFC  

Disables the use of the natural connection , and uses instead the symmetric connection . The natural connection and its differences as compared to the symmetric connection is described in Ref. [34, 50].

As the symmetric connection may give numerical inaccurate results, it's use is not recommended for other than comparisons with other programs.

.NOHESS  

Turns off the calculation of the analytical molecular Hessian . This option overrides any request for the calculation of molecular Hessians.

.NOLOND  

Turns off the use of London atomic orbitals  in the calculation of molecular magnetic properties. The gauge origin is by default then chosen to be the center of mass. This can be altered by the keywords .NOCMC   and .GAUGEO  .

.NOMASV  

Turns off the calculation of the mass-velocity  correction. By default the two relativistic corrections to the energy, the mass-velocity and Darwin corrections , are calculated perturbatively.

.NQCC  

Calculates the nuclear quadrupole moment coupling constant  .

.PHASEO  

READ (LUCMD, *) (ORIGIN(ICOOR), ICOOR = 1, 3)

Changes the origin of the phase-factors entering the London atomic orbitals. This will change the value of all of the contributions to the different magnetic field dependent properties when using London atomic orbitals. To be used for debugging purposes only.

.POLARI  

Invokes the calculation of frequency-independent polarizabilities . See the keyword .ALFA   in the *ABALNR   input module for the calculation of frequency-dependent polarizabilities.

.POPANA  

Invokes a population analysis   based on the dipole gradient as first introduced by Cioslowski [20]. This flag also invokes the .DIPGRA   flag.

.PRINT  

READ (LUCMD, *) IPRDEF

Set default print level for the calculation. Read one more line containing print level. Default print level is the value of IPRDEF from the general input module.

.QUADRU  

Calculates the molecular quadrupole moment . This includes both the electronic and nuclear contribution to the quadrupole moment. These will printed separately only if a printed level of 2 or higher has been chosen. Note that quadrupole moment is defined according to Buckingham [23], and it is not transformed to the principal moments of inertia coordinate system.

.RAMAN  

Calculates Raman intensities , as described in Ref. [22]. This property needs a lot of settings in order to perform correctly, and the reader is therefore refered to Section , where the calculation of this property is described in more detail.

.REPS  

READ (LUMCD, *) NREPS
READ (LUMCD, *) (IDOSYM(I),I = 1, NREPS)

Consider perturbations of selected symmetries only. Read one more line specifying how many symmetries, then one line listing the desired symmetries. This option is currently only implemented for geometric perturbations.

.RESTAR  

Restart in the property evaluation section. This keyword is currently disabled.

.SELECT  

READ (LUCMD,*) NPERT
READ (LUCMD, *) (IPOINT(I),I=1,NPERT)

Select which nuclear geometric perturbations are to be considered. Read one more line specifying how many perturbations, then on a new line the sequence of perturbations to be considered. By default, all perturbations are to be considered, but by invoking this keyword, only those perturbations specified in the sequence will be considered.

The perturbation ordering follows the ordering of the symmetrized nuclear coordinates. This ordering can be obtained by setting the print level in the *READIN module to 20 or higher.

.SHIELD  

Invokes the calculation of nuclear shielding  constants. By default this is done using London orbitals  in order to ensure fast basis set convergence as shown in Ref. [29, 30]. The use of London orbitals can be disabled by the keyword .NOLOND.

Furthermore, the natural connection  (Ref. [34, 50]) is default in order to ensure numerically stable results as well as physically interpretable results for the paramagnetic and diamagnetic terms. The natural connection can be turned off and instead use the symmetric connection  by the keyword .NODIFC.

The gauge origin  are chosen to be the center of mass  of the molecule. This origin can be changed by the two keywords .GAUGEO and .NOCMC . This choice of gauge origin will of course not affect the final shieldings, only the size of the dia- and paramagnetic contributions.

.SPIN-R  

Invokes the calculation of spin-rotation  constants as described in Ref. [44]. By default this is done using London orbitals  and the natural connection . The use of London orbitals can be turned off by the keyword .NOLOND.

By definition the gauge origin  of the spin-rotation constant is to be the center of mass  of the molecule, and although the gauge origin can be changed through the keywords .NOCMC and .GAUGEO, this is not recommended, and may give erroneous results.

In the current implementation, symmetry dependent nuclei cannot be used during the calculation of spin-rotation constants.

.SPIN-S  

Invokes the calculation of indirect nuclear spin-spin coupling  constants. By default all spin-spin couplings between nuclei with naturally occuring isotopes with abundance more than 1% and non-zero spin will be calculated, as well as all the different contributions (Fermi contact, dia- and paramagnetic spin-orbit and spin-dipole)    . The implementation is described in Ref. [33].

As this is a very time consuming property, as well as requiring MCSCF wave functions in order to get reliable results, it is recommended to consult the chapter describing the calculation of NMR-parameters (Ch. ). The main control of which contributions and which nuclei to calculate spin-spin couplings between is done in the *SPIN-S module.

.VCD  

Invokes the calculation of Vibrational Circular Dichroism (VCD)   according to the scheme described in Ref. [48]. By default this is done using London orbitals  in order to ensure fast basis set convergence as shown in Ref. [51]. The use of London orbitals can be disabled by the keyword .NOLOND.

Furthermore, the natural connection  (Ref. [34, 50]) is default in order to ensure numerically stable results. The natural connection can be turned off and instead use the symmetric connection  by the keyword .NODIFC.

The gauge origin  are chosen to be the center of mass  of the molecule. This origin can be changed by the two keywords .GAUGEO and .NOCMC . This will of course not affect the final VCD results, only the size of the contributing mechanisms.

In the current implementation, the keyword .NOCMC   will be set true in calculations of Vibrational Circular Dichroism, that is, the coordinate system origin will be used as gauge origin.

.VIBANA  

Invokes a vibrational analysis  in the current geometry. This will generate the vibrational frequencies in the current point. If combined with .DIPGRA the IR intensities will be calculated as well .

.VROA  

Invokes the calculation of Vibrational Raman Optical Activity  , as described in Ref. [22]. This property needs a lot of settings in order to perform correctly, and the reader is therefore refered to Section , where the calculation of this property is described in more detail.

.WRTINT  

Forces the magnetic first-derivate two-electron integrals to be written to disc. This is default in MCSCF calculations, but not for SCF runs. This file can be very large, and it is not recommended to use this option for ordinary SCF runs.