Townsend ionization constants in n-alkanes

We recently measured the first Townsend ionization coefficient, α in a series of n-alkyl chloride gases¹, and found that the dependence of α upon molecular structure in these gases was similar to, but different in detail from, that indirectly inferred in the hydrocarbon gases by Devins and Crowe² and Heylen and Lewis³ from sparking potential measurements. In order to determine whether these differences are real or are the result of errors in analysis of the sparking potential data, we have undertaken the direct measurement of the first Townsend ionization coefficients in the n-alkane gases containing from one to six carbon atoms.