Notes on the excitation processes in helium

Abstract

In the preceding paper an account has been given of experimental work on the excitation function of helium. Here we propose to enter into a fuller discussion of some of the problems involved. We shall give a detailed examination of the phenomenon of spreading, reported in the previous work; and also we shall put forward a rough but simple conception of the excitation process which allows an understanding in terms of elementary ideas of the main characteristics of the excitation process.