Measurement of integrated intensities in inelastic neutron scattering

Abstract The use of integrated intensities in neutron inelastic scattering measurements has become an increasingly important source of information for understanding a variety of problems in lattice dynamics. The use of intensity information in studies of both solid helium and neon has permitted investigators to determine the multiphonon character of some spurious peaks observed in constant - Q scans. The single-phonon character of similar unexpected peaks observed in the [100] direction of the alkali metals also could have been determined by intensity considerations. We report here that spurious peaks (that is, unexpected by symmetry consideration) of single-phonon character are quite naturally observed at small wave vector, q , in all crystalline substances. Furthermore, we show that the integrated intensities of all the observed peaks may be properly accounted for by suitable sumrule considerations. This is demonstrated for [100]L measurements on copper for | q | as small as 0.06 A −1 .