Lets' say I have a solid nanomaterial made with N atoms in a simulation box with a volume of V as shown below. In this case, the number density of my material is simply $\frac{N}{Volume\; of \; occupied\;3D\; space}$.

Solid Sphere

but what if I have a nanomaterial with $N$ atoms in the same simulation box, but $N_{1}$ atoms are in the solid phase and $N_{2}$ atoms are in the gas phase $\left( N_{1} + N_{2} = N \right)$.

enter image description here

How should I calculate the number density of my material in this case? Do I consider the whole box volume $V$? do I have to find an average over the whole material?

  • 1
    $\begingroup$ To keep things from getting too long here, I moved the discussion to chat $\endgroup$
    – Tyberius
    Oct 23, 2022 at 3:07
  • $\begingroup$ Have you figured out the answer over the last 8 months? Please update us! $\endgroup$ Jun 11, 2023 at 17:00