Experimentally, anisotropy factor is calculated by dividing the CD (circular dichroism) spectra by the absorbance spectra and multiplying by a factor of 32980 (in order to get a dimensionless quantity).
Theoretical calculations can be performed via TDDFT to obtain rotatory and oscillatory strengths, obtaining excitations for each case and adjusting, for each excitation, a curve, obtaining then the "theoretical absorbance/CD spectra".
How can then we define a theoretical anisotropy factor: Does it make sense? Should another calculation be performed?
Would you divide both adjusted curves or divide the corresponding excitations, adjusting a new set of curves to what you get?