Computer study of a classical quadrupole solid. II

Abstract

The Monte Carlo method is used to study the properties of classical free rotors with first‐ and second‐neighbor electric quadrupole interactions. The study is carried out for 108 particles on an fcc lattice and for 96 particles on an hcp lattice. Good agreement is found with transition temperature, latent heat, Raman scattering, and NQR results for N₂, taking the interaction constant Γ/k_B=3.1°K. In particular, the transition temperature for the classical system is found to be k_BT₀ = (12.7±0.3) Γ. The hcp structure appears to undergo a two‐dimensional ordering with no thermal anomaly. Susceptibilities and frequencies for quadrupole fields with certain wavevectors, which may be measurable by neutron scattering, are presented for both lattices.