The temperature dependence of the condensation and evaporation
pressures is shown in Fig. 8a. We see that the condensation
curve of the neck crosses the evaporation curve of the cavity at a
dimensionless temperature, h = (T–Ttr)/(Tc–Ttr), of about 0.17.
When h is greater than 0.17, the condensation and evaporation
curves for the cavity are distinct from the corresponding curves
for the neck, reflecting the existence of two distinct hysteresis
loops. The first loop, associated with the neck, disappears at
h = 0.4, which is the critical hysteresis temperature of the neck.
Thus, when h is greater than 0.4, there is a single hysteresis loop,
associated with the cavity, which decreases in area with temperature
and disappears at the critical hysteresis temperature of h = 0.7.
When h is less than 0.17, there is a fused hysteresis loop, the
first portion being due to the neck and the second to the cavity.
When h < 0.1 (below the triple point), the evaporation of the neck
is higher than that of the cavity, we observe a single hysteresis loop
with the sharp jump in the adsorption branch associated with the
neck.