If the block key AORESPONSE is used, by default, the polarizability is calculated. This can be modified using one of the keys below. Note that if the molecule has symmetry the key ALLPOINTS should be included.
AORESPONSE
OPTICALROTATION
VELOCITYORD
MAGNETICPERT
MAGOPTROT
RAMAN
FREQUENCY Nfreq freq1 freq2 ... freqN units
FREQRANGE freq1 freqN TotFreq units
LIFETIME width
ALDA|XALPHA
END
ALLPOINTS
OPTICALROTION
Specify OPTICALROTION to calculate optical rotatory dispersion spectrum instead of polarizabilities.
VELOCITYORD
This option should be used instead of OPTICALROT with GIAO if the finite lifetime effects need to be taken into account (LIFETIME option).
MAGNETICPERT
Calculate static or time-dependent magnetizability.
MAGOPTROT
Specify MAGOPTROT to calculate the Verdet constant instead of polarizability. When it is specified together with the LIFETIME key the real and imaginary part of the damped Verdet constant will be calculated. Combination of three keys MAGOPTROT, LIFETIME and FREQRANGE yields the magnetic optical rotatory dispersion and magnetic circular dichroism spectrum (Faraday A and B terms) calculated simultaneously in the range from freq1 to freqN. It is also possible to combine MAGOPTROT, LIFETIME and FREQUENCY. In order to obtain the Faraday B terms from the Verdet constant calculations it is necessary to perform several steps, involving a fit of the imaginary Verdet data to the MCD spectrum. You can request SCM for details on the fitting procedure. For details of the method, see Ref. [272].
RAMAN
Calculates the Raman scattering factors. The AOREPONSE-Raman only works with one frequency. If one frequency is specified the Raman scattering factors are calculated at that frequency. The Raman option is compatible with the lifetime option so that resonance Raman scattering can be calculated. For details of this method, see Ref. [266]. To get Raman intensities with AORESPONSE, numerical frequencies need to be calculated using a FREQUENCIES key in the GEOMETRY input block. Non-resonance Raman intensities can also be obtained using the RESPONSE key or, alternatively, using RAMANRANGE in combination with analytically or numerically pre-calculated frequencies.
FREQUENCY Nfreq freq1 freq2 ... freqN units
To calculate time-dependent properties, one needs to specify frequency of perturbation field. Here Nfreq specifies the number of frequencies that follow. The last item on the line specifies the units and is one of EV, HARTREE, ANGSTROM.
FREQRANGE freq1 freqN TotFreq units
This key is useful when it is necessary to specify more than 20 equally spaced frequencies for the response calculations. The first frequency is freq1 and the last one is freqN. The total number of frequencies including the first and the last one is TotFreq. The last item specifies the units: EV, HARTREE or ANGSTROM.
LIFETIME width
Specify the resonance peak width (damping) in Hartree units. Typically the lifetime of the excited states is approximated with a common phenomenological damping parameter. Values are best obtained by fitting absorption data for the molecule, however, the values do not vary a lot between similar molecules, so it is not hard to estimate values. A value of 0.004 Hartree was used in Ref. [266].
ALDA|XALPHA
If ALDA is specified the VWN kernel is used. This option is the default. If ALPHA is specified the Xα kernel is used instead of the default VWN one.
