H4eDesorption from Single Wall Carbon Nanotube Bundles: A One-Dimensional Adsorbate

The desorption of ${}^4\mathrm{He}$ from single wall carbon nanotube bundles has been measured for $T>\mathrm{}14\mathrm{}\mathrm{K}$. The adsorbate is approximately described by one-dimensional adsorption with a binding energy $\varepsilon =330\mathrm{}\mathrm{K}$. This binding energy is the largest measured for any charge neutral surface. Theoretical studies predict such a high binding energy for an adsorbate located in the interstitial sites of the single wall carbon nanotube bundles. We find a ${}^4\mathrm{He}$ interparticle distance of $\sim 3\mathrm{nm}$ at $14.2\mathrm{K}$ at a pressure of ${10}^{-6\mathrm{}}\mathrm{torr}$.