摘要

Light scattering proceeding through electric and magnetic dipole absorption events (E1-M1) exhibits natural circular dichroism, widely used in the characterization of chiral media, and the magneto-chiral effect, which is under consideration as a mechanism for the homo-chirality of life. Additional manifestations of E1-M1 scattering are resonance enhanced Bragg diffraction and non-reciprocal linear dichroism. In spite of its established importance for a raft of significant phenomena, there has not been a complete treatment of E1-M1 light scattering by electrons. Starting from the interaction that includes both electron spin and angular momentum variables, we construct scattering that proceeds via a spin-orbit split intermediate state for the photo-ejected electron. Employing new relations for re-coupling angular momentum we give a theoretical basis for the derivation of sum-rules for integrated dichroic signals. In order to assist in the interpretation of the algebraic terms present for E1-M1 we construct a family of equivalent operators that include monopoles for chirality and magnetic charge. Worked examples of corresponding expectation values are given for two sample wave functions to demonstrate the flavour and support the use of specific equivalent tensor operators.

  • 出版日期2010-7