The discussion centers on the phenomenon of optical activity in chiral molecules and how these molecules rotate light. Participants explore the physical mechanisms behind this rotation, including the role of electric fields and electron polarization, as well as the implications of molecular symmetry.
Participants express varying levels of understanding and confusion regarding the mechanisms of optical activity, with no consensus reached on the explanations provided. Multiple viewpoints and questions remain regarding the nature of electron polarization and its effects.
There are unresolved questions about the definitions and implications of polarization in the context of electromagnetic fields and molecular symmetry, as well as the specific conditions under which certain molecular orientations affect light rotation.
DrDu said:The electric fields of the optical wave polarize the electron clouds. The moving polarization of the electron clouds in turn leads to electrical fields which are partially emitted. However, the electric fields are not always emitted at the same point where the polarization and currents have been induced. If the resultant fields are furthermore rotated with respect to the incoming wave due to the low symmetry of the molecule, the polarization axis of the resultant field will be rotated.
Electric fields exert forces on the electrons and oppositely on the nuclei. Hence the centers of charge will separate and you will get a polarisation varying with the frequency of the incoming light. However, if the molecule isn't symmetrical, the polarisation will not be strictly along the direction of the incoming field. Hence the field of the fluctuating dipoles will be tilted as compared to the incoming field, i.e. the plane of polarisation gets rotated.Vivek des said:How does the electron cloud gets polarized?