Wetting of Argon on CO 2

We have studied the wetting transition of Ar adsorbed on solid CO2 by means of high-precision adsorption isotherms measured with a quartz microbalance. We observe triple-point wetting. At variance with many theoretical studies based on a model adsorption potential, which predict for this system a genuine prewetting transition around 100K we find that a detailed density-functional calculation employing a more realistic adsorption potential leads to triple-point wetting of Ar on CO2, in good agreement with the experiment.