Spin-polarized electron transmission through chiral halocamphor molecules

We have measured electron-circularly-dichroic asymmetries when longitudinally-polarized (chiral) electrons are scattered quasi-elastically by chiral halocamphor molecules: 3-bromocamphor (C10H15BrO), 3-iodocamphor (C10H15IO), and 10-iodocamphor. The proposed dynamic origins of these asymmetries are considered in terms of three classical models related to Mott scattering, target electron helicity density, and spin-other-orbit interactions. The asymmetries observed for 3-bromocamphor and 3-iodocamphor scale roughly as Z 2 , where Z is the nuclear charge of the heaviest atom in the target molecule, but the scaling is violated by 10-iodocamphor, which has a smaller asymmetry than that for 3-iodocamphor. This is in contrast to the asymmetries in the collision channel associated with dissociative electron attachment, in which 10-iodocamphor has a much larger asymmetry. All of the available electron-circularly-dichroic data taken to date are considered in an effort to systematically address the dynamical cause of the observed chiral asymmetries.