Phonon Dispersion Relations in NaCl

摘要: Phonon dispersion relations in NaCl at 80\ifmmode^\circ\else\textdegree\fi{}K have been determined the crystallographic [100], [101], and [111] symmetry directions using inelastic neutron scattering. Some measurements also made 300\ifmmode^\circ\else\textdegree\fi{}K, (1.0, 0.5, 0) reciprocal space. The results are compared with theoretical calculations: those of Karo Hardy for their "deformed-dipole" model, Schr\"oder N\"usslein a "breathing-shell" Caldwell Klein shell model. Satisfactory agreement is obtained many places, but significant discrepancies still remain, particularly close to zone boundaries. Comparison earlier x-ray work on NaCl. was performed new crystal spectrometer R2 reactor Studsvik, which equipped two-crystal monochromator.