Abstract
The incoherent inelastic neutron scattering spectra of hexamethylene tetramine (HMT) and adamantane have been measured at high resolution between 200 and 1000 cm-1. The agreement between the frequencies of the observed spectra and the optical spectra of Mecke and Spieseche (HMT) and Bailey (adamantane) is good. The observed neutron spectra are also matched very closely by the calculated one-phonon spectra, computed from a normal-coordinate analysis. There is some additional structure in the neutron spectra which appears to be due to multiphonon scattering involving lattice modes.