Vapor-Pressure-Isotherm Study ofN2on Graphite near the Tricritical Point

The commensurate solid and fluid coexistence region of monolayer ${\mathrm{N}}_2$ on graphite was mapped out in an exhaustive vapor-pressure-isotherm study. The tricritical exponent ${\beta }_t$ that describes the shape of the coexistence boundary was found to be equal to 0.55 ± 0.02, in very good agreement with recent theoretical predictions. The tricritical temperature, the end point of coexistence, was found to be 85.37±0.06 K.