COMPARATIVE NEUTRON-SCATTERING STUDY OF MOLECULAR ORDERING IN D-CAMPHOR AND DL-BORNEOLE

Molecules of both studied substances: d-camphor and dl-borneole are ne arly globular in shape and show plastic behaviour at room temperature. Neutron scattering investigations have been performed down to a heliu m temperature under different hydrostatic pressures up to 400 MPa. Neu tron diffraction (ND) and incoherent inelastic neutron scattering (IIN S) spectra clearly show the existence of phase transition in d-camphor , which has not been observed in dl-borneole. The ND spectra point to a possible cubic structure of dl-borneole crystal down to helium tempe ratures; temperature dependence of the IINS spectra suggests continuou s transition from dynamical to static disorder of molecules in this cr ystal.