Abstract
The scattering structure factor S(Q) describing distortions induced by a substitutional defect in a simple metal has been calculated from lattice statics and Shaw model potentials; interactions of arbitrary range can be included via reciprocal lattice sums. Diffuse elastic neutron-scattering measurements on Al single crystals with a few at.% Mg confirm the dependence on the momentum transfer hQ predicted for a Mg impurity in Al. Phenomenological fits assuming forces acting upon the next-nearest neighbours of a solute atom cannot explain that dependence.