Higher-Order Phase Transitions in N2 Monolayers Adsorbed on Basal-Plane Graphite
Abstract
Heat capacity and vapor-pressure measurements indicate a higher-order phase transition in nitrogen monolayers adsorbed on basal-plane graphite. The transition coincides with finite jumps in three experimental quantities: the two-dimensional compressibility, the isosteric heat of adsorption, and the heat capacity at constant area. Thermodynamics implies that the heat capacity at constant two-dimensional spreading pressure also has an abrupt jump and hence the transition is suggestive of a second-order Ehrenfest type.
- Publication:
-
Physical Review Letters
- Pub Date:
- December 1975
- DOI:
- 10.1103/PhysRevLett.35.1718
- Bibcode:
- 1975PhRvL..35.1718B