Extending the J-walking Monte Carlo algorithm to the isothermal–isobaric ensemble: solid–liquid equilibrium in clusters

The J-walking Monte Carlo algorithm is extended to the isothermal–isobaric ensemble (NPT) in order to reduce the problem of quasi-ergodicity encounter in the standard Monte Carlo procedure. Anomalies in the constant-pressure heat capacity as a function of temperature are identified an associated to the solid–liquid equilibrium. The maximum in temperature in this transition region is used for the construction of P–T phase diagram. The new algorithm reduces the uncertainty in the heat capacity by an order of magnitude when compared to standard NPT Monte Carlo.