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International audience; Using a semi-classical approach, we have calculated electron-, proton-, and ionized helium-impact line widths and shifts for 40 Si IV multiplets. The comprehensive set of obtained data has also been used for investigation of Stark broadening parameter regularities within spectral series.

The diffuse profiles of P and R lines in the D-X system of H_2 are investigated in connection with the other electronic states interacting with the D state by high resolution spectroscopy. Previously it has been widely claimed that the predlssociation of the Π^+ substate of Spπ D^1Π_u occurs at the v=3 level and above. The dissociating energies of the 2pσ B ^1Σ_u^+, 3pσ B' ^1Σ_u^+, and 2pπ C^1Π_u states H(1s)+H(2s, 2p) correspond to those between the v=2 and 3 levels of the D state. Among of them the state, mostly responsible to the predissociation, is considered to be the B' state. The theoretically calculated potentials of the B' and D states assert the slightly decreased interactions with the growing v' at the J=1 levels of D for v=3-12. It is much preferable for the examination of the theoretical prediction to study the line profiles with high J. So far the investigation about D-X has been limited mostly to R(0) and R(1). We focus the study on the R(J) lines with J=2 and 3 for v'≧6. Consequently, the slightly increased line widths with the growing v' are found against the theoretical prediction.

A review is given on the methods for X-ray line profile analysis. The transformation of a nickel hydroxynitrate into the hydroxyde is characterized., Une revue des méthodes d'analyse des profils de raies de diffraction des rayons X est effectuée. La transformation d'un hydroxynitrate de nickel en hydroxyde est suivie.

Dislocations are known for their peculiar effects on the diffraction profiles. Each given dislocation type, produces specific anisotropic line broadening basically determined by the so-called contrast factor (CF). Owing to the lack of a suitable mathematical frame to deal with dislocations in crystal of any symmetry, CFs have been so far determined for high symmetry materials. In this work we present the main points of a general approach for determining CF, as well as a specific application to scheelite CaWO4.