METASTABLE ATOMS AND ELECTRONS 287 



equivalent of the velocity with which the electrons are emitted from the 

 cathode, /o is the theoretical saturation current density of the electrons 

 emitted from the cathode, A. is the mean free path of electrons, and C is the 

 electrostatic capacitance between the two electrodes (expressed in centi- 

 meters). Experiments show that this equation expresses well the volt 

 ampere characteristics of neighboring electrodes in neon exposed to reso- 

 nance radiation. 



