Thermal neutron scattering by Debye solids: A synthetic scattering function

In most neutronic calculations, either to account for the effect of lattice vibration on nuclear resonances, the contributions due to multiple scattering processes or the presence of sample container in scattering experiments, the neutron-solid interaction is represented in a rather crude way, usually through a simple gas model. In this work we introduce a synthetic scattering kernel to describe incoherent neutron scattering processes in Debye solids. The model is based on a new prescription to represent the many-phonon contribution, whereas the first three terms of the phonon expansion are explicitly included. This prescription, which contains no adjustable parameters, is given in terms of analytical functions that produce a very good approximation to the sum of multiphonon terms. We present a few selected applications of this new method, using vanadium as a case to illustrate its merits and limitations. (C) 1997 Elsevier Science Ltd.