Calculations of positron and electron ejection cross sections are made for collisions of Ps $\left(1s\right)$ with the noble gases He, Ne, Ar, Kr, and Xe, allowing for target excitation (i.e., discrete excitation and ionization). Cross sections doubly differential and singly differential with respect to ejected energy and angle are reported, as well as total ionization cross sections. Our results show clearly that excitation of the target becomes very important at impact energies greater than about 2 times the ionization threshold of the atom. Comparison is made with absolute experimental measurements on He and Xe targets and, with one exception, good agreement is found at both total and single differential levels. Unfortunately, most of the measurements are at impact energies where target excitation is small or negligible. There is a need for experiments at higher impact energies to assess the predictions for target excitation.

• Received 29 January 2008

DOI:https://doi.org/10.1103/PhysRevA.77.042505