Thermal diffusion in mixtures of the inert gases

Since the independent prediction of the thermal diffusion effect by Chapman (1916) and by Enskog (1911) and its experimental verification by Chapman and Dootson (1917), the general nature of the phenomenon has been extensively studied by a number of workers, and its power in giving information on intermolecular fields has been demonstrated. The present work deals with all the binary mixtures of helium, neon, argon, krypton and xenon. These mixtures of inert gases are of special interest owing to the simplicity of the monatomic molecules. A few pairs of these gases had previously been examined by us (Ibbs and Grew 1931) as part of the general investigation of the effect, but it seemed desirable to work through the whole group systematically so that the behaviour could be studied under practically identical conditions.