Angular distribution of electrons emitted in Penning ionisation and similar processes

Abstract

The probability amplitude V_lambda for the emission of an electron in a certain partial wave lambda with projection m onto the internuclear axis can be defined within the Born-Oppenheimer approximation. Formulae which relate these quantities to the experimentally measurable electron angular distribution in the laboratory frame are derived. Further it is shown that the quantities V_lambda can be derived from experimental angular distributions in a rather straightforward way once the complex interaction potential V*-¹/₂i Gamma between the colliding atoms is known. An 'internal' angular distribution is defined and its simple connection to the laboratory distribution is given.