Exact limiting relation between the structure factors in neutron and X-ray scattering
Joint Institute for High Temperatures, Russian Academy of Sciences - 13/19, Izhorskaia Str., Moscow 125412, Russia
Accepted: 27 September 2010
The ratio of the static matter structure factor measured in experiments on coherent X-ray scattering to the static structure factor measured in experiments on neutron scattering is considered on the basis of the two-component electron-nuclear description of substances. It is shown that this ratio in the long-wavelength limit is equal to the nuclear charge at arbitrary thermodynamic parameters of a pure substance in a disordered state. This statement is the exact result of statistical mechanics in contrast to the similar approximate relation for the electron-ion plasmas, containing complex ions.
PACS: 31.10.+z – Theory of electronic structure, electronic transitions, and chemical binding / 05.30.-d – Quantum statistical mechanics / 52.27.Gr – Strongly-coupled plasmas
© EPLA, 2010