A molecular model of p-terphenyl and its disorder–order transition Original Research Article

An all-atom empirical potential is presented for p-terphenyl and compared with models in the literature. The model predicts correctly the structure of the crystal above and below the disorder–order transition. The ring flip dynamics in the model is in good qualitative and fair quantitative agreement with X-ray, neutron and NMR measurements: far above the transition, ring flipping is a local, activated process in an effective double-well potential; near the transition fluctuations grow in size and lifetime; below the transition, individual phenyl rings are locked in four inequivalent positions.