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The endothermal fine-structure transition (3P2 → 3P0—175 meV) of metastable argon atoms traversing at a velocity of 1030 m/s a micro-slit copper grating the normal axis of which is set, in a first configuration, at 60° with respect to the incident beam axis, is observed. The related differential cross-section (DCS) is sharply peaked at 60° and its velocity dependence reveals the expected threshold at 900 m/s. In a second configuration, the grating is set at an angle of 43°, allowing for a 7% transmission of the incident beam. Atoms elastically scattered by the corner edges of the grating slits are observed in the angular range 1°–4° and the elastic DCS is measured in relative values. In spite of such a widely unsuited geometry, the endothermal process still appears (with a magnitude 10 times smaller than before), because of the surface corrugation. The inelastic DCS is now peaked at 57.5° with a width of about 6°, as predicted from the corrugation angle distribution deduced from the inelastic DCS of metastable N2* molecules traversing the same grating.

This paper focuses on the link between noninteger differentiation and fractal lattices dimension. Extending Clerc's works, the Sierpinski gaskets, considered as electrical circuits, are studied for three different spatial dimensions: dimensions two, three and δ (with δ∈ R + ). Finally a calculation demonstrates the link between the dimension lattices and the fractional order characterising their frequential behaviour.

The paper deals essentially with the generalized derivative. The formalism is applied to the numerical solving of a generalized differential equation. It then deals with the numerical solving of a generalized characteristic equation. >