Electric Strength of Saturated Hydrocarbon Gases

Abstract

An attempt has been made to correlate the sparking potentials of nonattaching polyatomic gases with molecular structure. The investigation has included the normal alkanes containing from one to six carbon atoms, their branched chain isomers, cyclopentane, and cyclohexane. For a given electrode separation and pressure, the electric strengths of the normal alkanes increase with increasing chain length. Using a Townsend‐like criterion for breakdown it has been possible, with certain assumptions, to calculate from the measurements relative cross sections for electron scattering by these molecules. This scattering cross section is proportional to the number of carbon‐hydrogen bonds in the molecule, and independent of the number of carbon‐carbon bonds. It is independent of molecular shape, i.e., of branching or cyclization.