The Born theory of optical activity in quantum-mechanical form is simplified with the aid of certain approximations. It leads to a simple expression for the rotatory parameter of an active molecule in terms of the geometrical configuration and the polarizability tensors of its constituent groups. Optical anisotropy of the component groups and inhibited internal rotation are found to play an important role in determining rotatory power. The proposed theory has points of similarity both with the polarizability theories of Gray, de Mallemann, and Boys and also with Kuhn's specialization of Born's classical theory of optical activity. To illustrate its use, the absolute configuration and the specific rotation of d-secondary butyl alcohol are calculated.

In dilute aqueous solutions, D-glyceraldehyde exists both in the free and hydrated monomeric forms; the equilibrium between them depends on the temperature. The specific rotation of the equilibrium mixture was measured polarimetrically in the temperature range from 20 to 80 °C, the concentrations of both forms being determined by 1H NMR spectroscopy. From these data, the specific rotations of both forms of D-glyceraldehyde in the indicated temperature range were calculated.