Helium mixtures in nanotube bundles

An analog to Raoult’s law is determined for the case of a ${}^3\mathrm{He}{-}^4\mathrm{He}$ mixture adsorbed in the interstitial channels of a bundle of carbon nanotubes. Unlike the case of He mixtures in other environments, the ratio of the partial pressures of the coexisting vapor is found to be a simple function of the ratio of concentrations within the nanotube bundle.