# Example: Vibrational Raman optical activity (VROA): H2O2¶

Download VROA.run

Example shows a calculation of normal vibrational Raman optical activity.

In the ADF input one then needs to include the subkey FREQUENCIES of the key GEOMETRY (numerical frequencies) and include the subkey VROA of the key AORESPONSE. A laser frequency need to be added. The other keys in AORESPONSE are recommended by the author of the implementation of VROA in ADF. For accuracy reasons ‘NumericalQuality Good’ and EXACTDENSITY are used. Note that the subkey FitAOderiv is only used in case of pair fitting (STOFIT), in which case it will improve the fit quality. The default fit method is ZlmFit, which will not use this key. In case of ZlmFit one should set the numericalquality or ZlmFit quality to a high level, for example Good or VeryGood.

\$ADFBIN/adf << eor
title VROA TEST H2O2

basis
type TZP
core None
end

ATOMS
1.O        -0.750254   -0.034490    0.015133
2.O         0.750254    0.034490    0.015133
3.H        -0.943532    0.744006    0.580040
4.H         0.943532   -0.744006    0.580040
END

xc
gga BLYP
end

GEOMETRY
frequencies
END
exactdensity

NumericalQuality Good

aoresponse
NEWPOLCODE
VROA
scf  converge 1d-6 iterations 100
frequency 1 5145 Angstrom
ALDA
FitAOderiv
EL_DIPOLE_EL_DIPOLE VELOCITY