The critical exponent β associated with the two-dimensional condensation in the second adlayer of argon on the cleavage face of cadmium chloride

Adsorption isotherms of argon on the cleavage face of cadmium chloride have been measured in the vicinity of the critical point of two-dimensional condensation of the second adlayer. From these data we propose a value of 0·16 for the critical exponent β, reflecting the two-dimensional character of the transition.