Empirical intermolecular potentials for N2 and CO2 from crystal data

Lattice frequencies and energies are calculated with an n‐6 atom‐atom potential to fit recent Raman spectra of solid N₂ and neutron scattering data of solid CO₂. It is found that $\text{n\hspace{0.17em}∞\hspace{0.17em}9}$ provides a slightly better fit than the previously used n = 12. The atom‐atom potential, giving a fit of about 10% to experimental data, is compared with other potentials and it is pointed out that it can be modified and supplemented by other terms (a quadrupole potential) so as to yield a more realistic potential model, having the expected forms at the limits of large and small intermolecular distance.