Inelastic neutron scattering is an experimental technique commonly used in
condensed matter research to study atomic and molecular motion as well as magnetic and crystal field excitations. It distinguishes itself from other
neutron scattering techniques by resolving the change in kinetic energy that occurs when the collision between neutrons and the sample is an
inelastic one. Results are generally communicated as the
dynamic structure factor (also called inelastic scattering law) , sometimes also as the dynamic susceptibility where the scattering vector is the difference between incoming and outgoing
wave vector, and
is the energy change experienced by the sample (negative that of the scattered neutron). When results are plotted as function of
, they can often be interpreted in the same way as spectra obtained by conventional
spectroscopic techniques; insofar as inelastic neutron scattering can be seen as a special spectroscopy.