Inelastic neutron scattering studies of the torsional and librational modes of the anilinium halides, C6H5NH3X

Abstract

The low-frequency modes of vibration of the anilinium ion in the salts C₆H₅NH₃X (where X = Cl, Br or I) have been studied by inelastic neutron scattering, infrared and Raman spectroscopies. In addition, spectra of both the N- and C-deuterated analogues, and also of solid toluene, have been measured. Where possible we have identified the torsional modes of the C₆H₅— and —NH₃⁺ groups. Barriers calculated from the NH₃⁺ torsions have been compared with the energies of activation obtained from nuclear magnetic resonance studies.