The displacement-displacement correlation function in the case of an isotropic ionic crystal with several optic branches has been calculated to determine the inelastic-scattering neutron cross section. We have examined the feasibility of an experiment to measure the dispersion curves and the density of states of the polar modes. The infrared electromagnetic field outside the crystal associated with the polariton excitation has been considered and found directly related to the polariton density of states. Though relevant information can be gained by this kind of experiment, its feasibility seems to be subordinate to the planned fulfilment of the high-energy pulsed neutron sources.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics