Molecular dynamics of t e r t-butanol studied by neutron inelastic scattering

Molecular dynamics of tert-butanol in two crystalline phases and in the liquid state was investigated by cold neutron scattering in the temperature interval 8–35 °C. Inelastic spectra remained essentially the same, indicating short range order in the liquid state. A frequency spectrum obtained from the sum of seven Gaussian functions fitted the measured time-of-flight distribution and allowed assignment of peak positions. A barrier V1= (4.0±0.2) kcal/mol for CH3 internal rotation was obtained; results are compatible with a second order term V2?−0.1V1. Quasielastic line broadening and Debye–Waller factors were analysed in terms of models for molecular diffusion and the results compared with NMR data. It is concluded that cooperative rotational diffusion occurs both in solid and liquid states.