Electron dichroism - new data and an experimental cross-check

The spin-dependent attenuation of polarized electron beams transmitted through the vapour of chiral molecules was investigated in the electron energy range 0.5 - 10.0 eV. Several target molecules containing at least one atom of high atomic number were used in order to gain information about the role of the spin - orbit interaction in electron dichroism (ED). The results show that for quite different substances with one heavy atom the ED is of the same order of magnitude and that molecules with two heavy atoms do not necessarily show stronger ED. Some of the results indicate that the ED grows with increasing Z of the heavy atom. In some cases the transmission asymmetry reaches its largest values at those energies where resonances in the total cross section occur. In a second experiment it has been shown that an unpolarized electron beam, when transmitted through the vapour of bromocamphor, becomes longitudinally polarized. The value of this polarization and the measured transmission asymmetry correspond to each other, as predicted by theory.