  Comparisons of Gibbs ensemble Monte Carlo simulations with experimental data
for the cage occupancies in N2 clathrate hydrates are performed to assess the
accuracy of such simulations, to refine the effective potentials employed, and
to help interpret recently measured large cage over small cage occupancy ratios
[Petuya et al., J. Phys. Chem. C 122, 566 (2018)]. Different sets of
interaction potentials for N2-N2, N2-H2O and H2O-H2O interactions are
considered. Some of them fail to reproduce the known experimental fact that
some large cages are doubly occupied at 273 K and high pressures. The best
agreement between simulations and experiments is obtained when using a new N-O
interaction potential derived in this work by averaging an ab-initio potential
energy surface for the N2-H2O dimer.
