The osmotic pressure of liquid 3He- 4He mixtures at temperatures below the Lambda-point

Abstract

The osmotic pressure of liquid 3He- 4He mixtures, condensed in a vessel connected by means of a narrow slit to a similar vessel containing pure 4He, has been measured by determining the fountain pressure exerted by the pure 4He, when heated, necessary to obtain equilibrium with the osmotic pressure of the mixture. The osmotic pressure meets Van 't Hoff's law within a few percent up to 4% concentration. A revised vapour pressure — liquid concentration relation is given, based on the results, obtained at 1.2°K.