Final Generalization of the Three Coupled Oscillator Model in the   Crystal Optical Activity
  In this paper we generalize the quantum mechanical model of three coupled oscillators because of its usage in the crystal optical activity. Using this model we can include the influence of all essential couplings between single oscillators which represent the molecules or atoms of optically active crystals belonging for example to the space groups of symmetry D(3,4) or D(3,6). The single oscillators are damped and therefore we can include both parts of the optical activity - optical rotatory dispersion and circular dichroism - into computations. We present more universal formulas for description of the above mentioned parts. 
I. Vysin, K. Svackova