A polarization trip from Québec to Vancouver

Exactly 30 years ago the ICPEAC was held for the first time in Canada. At this conference in Québec first results on spin-polarization phenomena in low-energy electron scattering were presented. In the following years spin-polarization effects played an increasing role at the ICPEAC and its satellite conferences. This contribution gives a perspective of this development in the past 30 years. It outlines fundamental directions of development, shows how they interact, and gives an account of their usefulness for a better understanding of collision physics. In the first part, processes are discussed where the polarization effects are caused by either the spin–orbit interaction or the exchange interaction alone. Experimental results on such processes can be used to study the role of these spin-dependent interactions in electron-atom collisions. In recent years more complicated processes have been studied where the two spin-dependent effects can no longer be disentangled. Examples of such processes are elastic scattering from atoms with unsaturated spins, inelastic scattering, and spin-selected coincidence experiments. Major progress in spin-dependent scattering from chiral molecules will also be reported. The enormous progress of this field in the past 30 years could only be made by a number of novel developments in the production and detection of electron polarization.