Axial and circular birefringence due to static electric and magnetic field combinations

Abstract

Axial and circular birefringence are derived for a combination of static electric field strength (ES) and static magnetic flux density (BS). For ES parallel to BS in the Z axis of the laboratory frame (X, Y, Z) the refractive index measured in a chiral ensemble with unpolarized light with wave vector KZ, propagating in Z, is different for KZ parallel and antiparallel to ESZ for fixed BSZ or vice versa. The effect is c times greater in magnitude than axial birefringence due to BSZ alone and is proportional to the product BS⋅ES and to the ensemble average 〈A′1XXZZ〉, where A1 is an odd parity tensor mediating the effect of BS⋅ES on the molecular polarizability. Circular birefringence due to ES⋅BS also occurs in chiral ensembles only, but is c times smaller than axial birefringence. It is proportional to the ensemble average 〈A′2XXZZ〉, where A2 is an even parity tensor mediating the effect of ES⋅BS on the molecular Rosenfeld tensor. There are no equivalent effects due to ES alone, ES⋅ES or BS⋅BS, because they violate reversality. The ES⋅BS effects conserve reversality both in achiral and chiral ensembles, and provide information on new molecular property tensors. Their frequency dependencies provide novel molecular spectroscopies, and experimental configurations are suggested.