Net atomic charges, electric moments, and sign and magnitude of optical rotatory power in α-TeO 2 at 296 K

Optical activity is determined from a point charge model in one enantiomorph of a chiral and semiconducting α-TeO 2 crystal. Net atomic charges of Te and O atoms are iterated and electric moments derived. Second electric moments in the principal axis directions are calculated and their ratio is fitted by comparison with the corresponding ratio of the optical refraction indices. The components of the axial vectors are calculated and converted to the gyration tensor components. The optical rotatory power in the positive direction of the optic axis is determined, and the sense of optical rotation is defined from transformations of polar vectors of first rank of the TeO 2 groups and visually confirmed in both enantiomorphs.