Ionization by Collisions of the Second Kind in Mixtures of Hydrogen and Nitrogen with the Rare Gases

The effect of the presence of a rare gas in ionized hydrogen and nitrogen was studied by means of a positive ray analysis of the products of ionization. The variation with pressure of the types of ions found was investigated in some detail for both hydrogen and nitrogen in the presence separately of helium, neon and argon. In all of the mixtures studied the evidence tends to support the view that a type of collision of the second kind takes place at which an atom is ionized by colliding with an ion of an atom of higher ionizing potential. Thus at high pressures corresponding to a large number of collisions the equilibrium is displaced in favor of the atom of lower ionizing potential. The following equations can be predicted from a knowledge of the ionizing potentials and they are all supported by the experimental evidence obtained: Where ¹⁷N₂⁺ and ²⁴N₂⁺ represent respectively the nitrogen ions produced at the expense of seventeen and twenty-four volts.The situation for nitrogen is seen to be more complicated than that for hydrogen. In the latter case the evidence shows that the equations listed above are in the order of increasing probability. This tends to support the view that the probability of the transfer's occurring is an inverse function of the difference in ionizing potentials. The phenomena can not be interpreted as accurately in the case of nitrogen. However, the formation of ²⁴N₂⁺ by Ne⁺ (24.5) was found to be the most probable of all the processes occurring in nitrogen and the results obtained with the other rare gases as far as they can be interpreted are also in accord with this view.