TORSION INDUCED CIRCULAR-DICHROISM IN HEXAGONAL CDS

The influence of the torsion on the absorption properties of hexagonal CdS has been studied in our experiments. The undeformed CdS does not possess circular dichroism (CD) but it manifests linear dichroism (LD) . An appearance of CD and a change of LD can be observed in the torsio n deformed CdS crystals. The mentioned absorption phenomena occur in t he vicinity of the isotropic point (i.p.), the crossing point of the c urves of the refractive indices n(0)(lambda) and n(e)(lambda). The sig n of CD is connected with the direction of the torsional moment M. The magnitude of M influences the shape of CD spectra as well as the valu es of LD. The appearance of CD and the change of LD are explained by t he torsion induced gyrotropy in the CdS crystals, i.e. by the created chirality in the hexagonal CdS.