Diffusion, De-Excitation, and Ionization Cross Sections for Metastable Atoms. I

Abstract

The lifetimes of metastable atoms in gases are determined from studies of the ionization which they produce in the afterglow following a pulsed discharge. Two distinct types of ionizing reactions are studied, the first in which the collision of a pair of metastable atoms results in ionization of one of them and deexcitation of the other, the second in which a metastable atom of one type loses its excitation energy in ionizing a normal atom of another type. From studies of this ionization as a function of various experimental parameters such as gas pressure, we obtain values of the diffusion, de-excitation, and ionization cross sections of metastable helium and neon atoms. The various measured cross sections agree reasonably well with values obtained from modern optical absorption studies.