The problem of optical activity of a molecule, which is built up of several groups to each of which is attributed an isotropic resonator, has been treated by Born* in a paper with the same title (Part I and II). The method of approximation used there depends on the assumption of small coupling forces, i. e., large distances between the resonators. It seems of some interest to investigate whether active models can he found which may be treated without this assumption of large distances. A regular tetrahedron, the corners of which carry identical isotropic resonators, is not optically active. If, however, changes of shape and therefore of mechanical property are introduced which exclude a plane of symmetry, the system can be optically active. In this paper we consider a change brought about by a small twist of the regular shape of the tetrahedron. Two of the corner of the regular tetrahedron are kept fixed and the other two are rotated through a small angle, along a binary axis connecting the centres of the two edges. Such a system has evidently no plane of symmetry and it can be optically active.* The rotatory power can be calculated by a method of approximation. In this the regular tetrahedron is taken as the zero order approximation. We shall show that the optical activity is proportional to the third power of the small angle of twist.
No takes yet. Share an insight, caveat, or question.
B. Y. Oke (1936) studied this question.