Neutron Scattering Function in a Heisenberg Paramagnet: Application to KMnF₃

Abstract

The sum-rule moment method of Kadanoff and Martin has been extended to include higher-order terms and a continued-fraction representation of the generalized susceptibility has been derived. The scattering function (Remark: Graphics omitted.) based on the second-order Gaussian generalized diffusivity is essentially the same for small scattering vectors as that constructed in terms of a two-parameter Gaussian diffusivity by Tahir-Kheli and McFadden, but predicts for large scattering vectors a broad distribution in agreement with the results of the recent neutron scattering experiments on paramagnetic KMnF₃ at 3.4 T_N of Betsuyaku and Hamaguchi.