Der Einfluß des Winkelauflösungsvermögens auf die Messung totaler atomarer Streuquerschnitte.

Molecular beam measurements of total scattering cross sections require a very high angular resolving power of the measuring apparatus, which is often not attainable to a sufficient degree for reasons of beam intensity. Consequently the measured cross sections need a correction. The problem becomes complicated, if, as is customary, the geometry of beam and detector has no rotational symmetry about the beam axis. In this paper the average detection probability η(Θ), as defined by Kusch, is calculated for all common shapes of beam and detector. By use of the semiclassical differential cross section for an r potential, the correction to the total cross section is computed. At thermal energies and with an angular resolving power of about one minute of arc, the correction amounts to several percent and is therefore considerably greater than commonly assumed. [ABSTRACT FROM AUTHOR]