Example: Vibrational Raman optical activity (VROA): H2O2¶
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 EL_DIPOLE_EL_QUADRUPOLE VELOCITY EL_DIPOLE_MAG_DIPOLE VELOCITY end END INPUT eor
Note that used basis set is too small to get accurate results. Better is the use larger basis sets, like one of the even tempered basis sets (for example Type ET/ET-QZ3P-1DIFFUSE), or use augmented basis sets (for example Type AUG/ATZ2P).