A dynamic correlation function from inelastic neutron scattering data

For a non-dispersive vibrational mode in a solid the Q-dependence of the scattering function S(Q, E) at the energy of the mode contains information relating to the atomic displacements of the mode. An empirical approach to the analysis of such data has recently been employed whereby a Fourier transform is used to obtain a ‘dynamic correlation function’ in real-space. This technique is demonstrated using new data on amorphous boron. The theoretical basis of the method is discussed and it is shown that, whilst the result of the Fourier transform is not a true correlation function, the method is capable of providing information concerning the atomic distances which participate in a particular vibration and the relative phase involved.