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We used the x-ray-extended range technique to measure the x-ray mass attenuation coefficients of silver in the 15–50 keV energy range with a level of uncertainty between 0.27% and 0.4% away from the K-edge. The imaginary part of the atomic form factor of silver was derived by subtracting the scattering component from the measured total mass attenuation coefficients. Discrepancies between the measured mass attenuation coefficients and alternative theoretical predictions are discussed.

The properties of the ion feature of the Thomson scattering signal are investigated. Firstly, the description of the atomic form factor by hydrogen-like wave functions is reviewed and better screening charges are obtained. Then the ionic structure in systems with several ion species is calculated from the HNC integral equation.

It is supposed that the momentum transfer and atomic number dependence of the coherent scattering cross section may be described by the Thomas-Fermi variables. As a result of such consideration the semiclassical asymptotics of the atomic form factor is derived.

A comprehensive treatment is presented of integrals of the squared form factor for a fixed transition with respect to the momentum transfer. The integrals with different powers of the momentum transfer are related to different properties calculable from the transition density. Some of the integrals are useful for testing consistency of data obtained from independent sources, either theoretical or experimental. Applications include the integrated cross section for a definite transition, the total inelastic collision cross section, and the polarisation (or the angular distribution) of light emitted after collisions, all for impact of fast charged particles for which the first Born approximation is suitable.

The optical properties of clean, evaporated films of gallium have been studied at several temperatures. The observed spectra were interpreted on the basis of a pseudopotential calculation of the band structure. The position of characteristic peaks in the spectra agreed well with the predictions from the optimized model potential for gallium recently published by Appapillai and Williams (1973). The shift of the peaks with temperature was too large to be accounted for by shifts in the atomic form factor alone; the Debye-Waller factor must be included to explain the observations.

The atomic form factor and the incoherent scattering function of Ar calculated from the Bethe-Goldstone method are presented. The results include electron correlation effects in the M shell as well as those between the L and M shells. The form factor calculated from the Hartree-Fock wavefunction agree within 2% with the result from the Bethe-Goldstone method for a wide range of momentum transfer. However, the correlation effects reduce the incoherent scattering function for small momentum transfers (

The X-ray scattered intensity from a liquid metal as an electron-ion mixture is described using the structure factors, which are exactly expressed in terms of the static and dynamic direct correlation functions. This intensity for a metal is shown to differ from the usual scattered intensity from a non-metal in two points: the atomic form factor and the incoherent (Compton) scattering factor. It is shown that the valence electron form factor, which constitutes the atomic form factor in a liquid metal, leads to a determination of the electron-electron and electron-ion structure factors by combining the ionic structure factor. The authors clarify some confusion which appeared in the proposal by Egelstaff et al. (1974) for extracting the electron-electron correlation function in a metal from X-ray and neutron scattering experiments. A procedure to extract the electron-electron and electron-ion structure factors in a liquid metal is proposed on the basis of the formula for the scattered intensity derived.