Temperature and pressure constraints near the freezing point

The isothermal-isobaric ensemble molecular-dynamics method MD(T,p,N) proposed by Nosé and Hoover is used to study the fluctuations in a two-dimensional Lennard-Jones fluid, close to the freezing point. The T and p constraints in this method do not affect the dynamical behavior of the system, since spontaneous fluctuations in the density allow the system to freeze and melt just as do the T and p fluctuations in the microcanonical ensemble MD(E,V,N) close to the melting zone