Structure of solid t‐butyl cyanide: Interpretation of experimental data by means of molecular dynamics simulation

Molecular dynamics calculations have been carried out on the disordered phase I of solid t‐butyl cyanide. The nature of the orientational disorder has been investigated using a variety of intermolecular potentials based on site–site interactions between rigid molecules. The potentials were parametrized, in part, to the properties of the low‐temperature, monoclinic phase II. In phase I, rotation around the C–C≡N axis is found to occur on a picosecond time scale, in good agreement with deductions based on neutron scattering data. No evidence has been obtained for preferred orientations for the molecular symmetry axis. The intensities of Bragg and diffuse scattering have been calculated and compare favorably with neutron scattering results. The lattice vibrations have been investigated and it is found that the transverse acoustic phonons are heavily damped, at least for those wave vectors accessible in the simulations.