Ionizing Collisions of Very Fast Particles and the Dipole Strength of Optical Transitions

This note discusses how the Bethe theory of ionizing collisions should be adapted to gases other than atomic hydrogen. Experimental data on primary ionization, analyzed by the method of McClure, yield the value of the total dipole strength for ionization, ∫I^∞|xW|²dW, an atomic property which is otherwise poorly known and whose relationship to the diamagnetic susceptibility should be of interest.