Calculation of argon compressibility at different cooling rates

Techniques for the simulation of thermodynamic processes in molecular systems are proposed. The results of the calculation of the argon isothermal compressibility by the molecular dynamics method for isobar cooling from $200$ to $15$ K at a pressure of $40$ atm and an adiabatic compressibility in the range of $200$–$160$ K at $40$ atm are given. Steps, interpreted as phase transitions, are visible on the temperature dependences of the isothermal compressibility at fast $(10^{12}$ K/s$)$ and relatively slow $(10^9$ K/s$)$ cooling.