Magnetic circular dichroism in angular distributions of core-level photoelectrons

Magnetic circular dichroism in angle-resolved, core-level photoemission from surfaces is reinterpreted by comparing it to circular dichroism in angular distributions of photoelectrons in nonmagnetic systems. The analogy highly recommends the use of the terminology magnetic circular dichroism in angular distributions of photoelectrons for the former effect, since it emphasizes both the role of the photoelectron wave vector k, and the use of an experimentally induced chirality. Two phenomena are predicted in experimental geometries that do not have spatial mirror symmetry: first, the dichroism that results from reversal of the light helicity is not equivalent to what results from reversal of the sample magnetization; second, a linear dichroism exists upon reversal of the sample magnetization. The latter effect, termed ``magnetic linear dichroism in angular distributions,'' is a pure interference term, which disappears in an angle-integrated experiment, and may greatly simplify the study of magnetic-exchange effects at core levels.