Spin Polarization of Low-Energy Electrons Scattered Elastically from Atoms and Molecules

The $Z$ dependence of total spin polarization is systematically ascertained by tracing the trajectory of a particular zero of the scattered amplitude as a function of atomic number. The incident electron energy corresponding to 100% polarization is shown to increase linearly with increasing atomic number. In addition, it is found that total polarization is confined to a relatively narrow angular range for varying $Z$. Further calculations on the independent-atom model representation of electron spin polarization for electron-molecule collisions are given. Arguments leading to the improbability of obtaining enhanced polarization over the atomic case are presented. The most significant result of these calculations is the relative insensitivity of the spin polarization to the molecular parameters.