This application simulates the distribution of atoms or molecules between energy levels at a certain temperature T, in thermal equilibrium.
It works based on the Boltzmann distribution:
$$
P_n = \dfrac{ e^{ -E_n/k_B T } }{ \sum_{j=1}^N e^{ -E_j/k_B T } },
$$
where $P_n$ is the probability of finding a particle in state $n$.
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