Experimental studies on electron scattering from atoms and molecules: the state of the art

Electron-atom/molecule scattering has been the subject of intense research activity, both experimentally and theoretically, for nearly a century, yet particularly for electron-molecule scattering our understanding of the dyna mics of such processes remains limited. Due to their importance in many ind ustrial, astrophysical, atmospheric and biological processes, absolute elec tron-scattering cross-sections are required for most atomic and molecular s ystems, however, the current database is limited to a few easily prepared s ystems. Only recently have experimental studies been extended to unstable r eactive and free-radical species, while new experimental techniques incorpo rating advances in atom trapping and laser spectroscopy are being adapted t o provide new insight into electron collision dynamics. In this paper we survey the current status of the field and discuss the new experimental techniques that are providing fresh insights into the electro n-scattering problem while providing invaluable data for the applied-scienc e community.