Triple point dewetting transitions of helium mixtures on cesium.

D. Ross, J. E. Rutledge, and P. Taborek Department of Physics and Astronomy, University of California, Irvine, California 92717 (Received 9 November 1995) The adsorption of He-He mixtures on a cesium substrate has been measured near bulk liquid phase separation. A first order wetting transition is found on the bulk three phase coexistence line at Tw > 0.53 K. The He rich liquid phase wets the surface below Tw , and layered films of He rich liquid under a He rich layer wet the substrate above Tw . The surface phase transition line associated with this wetting transition is found to extend to both sides of the bulk coexistence line. On the He rich side it becomes a line of triple point induced dewetting transitions.