Optical activity of electronic transitions in the UV-Vis range is measured by electronic circular dichroism (ECD) as the difference in absorption of left and right circularly-polarized light, ∆ε. Whereas the absorption is theoretically connected to the oscillator strength of the transition, the chiroptical response is proportional to the rotatory strength of the transition, ∆ε ∝ R. In its simplest form, R is given by the product of the lengths of the electric (⃗ µ) and magnetic (⃗ m) transition dipole moment vectors and the angle given by their mutual orientation (θ ) as given in equation 1.