Test volume method

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An alternative to the virial pressure route to calculating the pressure, there is a method which consists on evaluating the change in internal energy, $\Delta U$ produced by a small change in the volume of the system $\Delta V$. It can be shown that
$p = \frac{ k_B T N}{V} + \frac{ k_B T }{ \Delta V } \log \langle \exp(-\Delta U/k_B T )\rangle,$
where $k_B$ is the Boltzmann constant and $T$ is the temperature.