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 dynamics of such processes remains limited. Due to their importance in many industrial, astrophysical, atmospheric and biological processes, absolute electron–scattering cross–sections are required for most atomic and molecular systems, however the current database is limited to a few easily prepared systems. Only recently have experimental studies been extended to unstable reactive and free–radical species, while new experimental techniques incorporating advances in atom trapping and laser spectroscopy are being adapted to 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 electron–scattering problem while providing invaluable data for the applied–science community.