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## Summary:

- How can I calculate a thermodynamic derivative like dE/dV (where E is internal energy) from a data that seem to be total kinetic and potential energy values?

I don't understand how to use output from an NPT molecular dynamics simulation to compute a thermodynamic derivative.

I need to compute this (where "d" is a partial derivative, "T" is a subscript that means, "at constant temperature," and "E" is internal energy):

I have a simulation output file that has these columns:

I think I need to add the kinetic and potential energy columns to get the internal energy. But how do I compute the partial of E with respect to V at constant T? E.g., what is the reference point for calculating the delta? Is it E at one time step minus E at the previous time step?

I have another file that provides the volume at each time step. It fluctuates because this is an NPT simulation.

Any hints would be very helpful. Thank you.

I need to compute this (where "d" is a partial derivative, "T" is a subscript that means, "at constant temperature," and "E" is internal energy):

**-(dE/dV)T**I have a simulation output file that has these columns:

**Time, temperature, kinetic energy, potential energy, total energy**I think I need to add the kinetic and potential energy columns to get the internal energy. But how do I compute the partial of E with respect to V at constant T? E.g., what is the reference point for calculating the delta? Is it E at one time step minus E at the previous time step?

I have another file that provides the volume at each time step. It fluctuates because this is an NPT simulation.

Any hints would be very helpful. Thank you.