Zur Zustandsdichte der übergangsmetalle

Abstract

An isochromat-spectroscopic investigation of the binary alloys Rh~Pd and Pd--Ag, including the pure elements, has shown that the measured X-ray isochromats can be described within a rigid-band model. A comparison of the isochromat and the continuous X-ray spectrum of Rhodium near the short wavelength limit supports the assumption that the intensity of the isochromat is proportional to the density of the unoccupied states in the conduction band. The absolute value of this density of states can be estimated from the isochromats by making use of the rigid-band model. When moving from Rh to Pd and Ag, there is a monotonous decrease in the density of states at the respective Fermi limits; there was no peak close to the Fermi limit of Palladium, which is a characteristic of the coefficient 7 of the electronic specific heat. This discrepancy can be explained by assuming that 7 is enhanced over the value corresponding to non-interacting electrons, e.g. by electron-phonon-interaction and by spin fluctuations. For this enhancement usually expressed by the mass enhancement, m*/m, an experimental value of m*/m= 5.3_ 1.0 for Palladium can be derived from the isochromat data and the 7-value of Palladium. Moreover, it can be concluded from the measurements that the d-band is full when more than (38__. 5) atomic percent Ag are alloyed to Pd.

Measurements of He-like Argon on TEXTOR, a benchmark Experiment for the ITER X-ray Spectrometer

“…Spherical, as well as toroidal crystals have been discussed. The imaging properties of spherical crystals have been used for high resolution spectroscopy and have been analysed in detail [2,3,4]. The imaging is highly astigmatic, a point on the on the focal plane is focused into two line foci, the meridional focus on the Rowland circle and the sagittal focus outside the Rowland circle.…”

Accurate miscut angle determination for spherically bent Bragg crystals

“…In this ͑Johann-type͒ setup, 4 defocusing due to the imaging properties can be well controlled by choosing appropriate dimensions for x-ray source, crystal, and its radius of curvature, in combination with a large area positionsensitive detector. 5 A general problem is that the precise knowledge of the orientation of the lattice planes of the slabs, cut from a crystal bulk and subsequently polished, may be lost. Deviations are due not only to an imperfect determination of the orientation of the bulk material but especially from alignment problems of the sawing machine.…”

The molar heat capacity of superconductive (PdRh0.06)Hx in the temperature range from 2 to 7.5 K

“…An analysis of the maximum appears to be reasonable a s it is important for the discussion of the results for the samples with x > 0.always only indirectly the bare state density at the Fermi limit N (EJ , since with both quantities an enhancement by electron-phonon interaction h and electronmagnon interactions h is possible. According to (6) to(8) the behaviour o f t and x a s a function of the Rh content of the alloy is in no way related to the behaviour of N (E ). On the basis of other papers it may be assumed that at 5 at% Rh a maximum of No(EF)(9) to (12) and simultaneously a maximum for hE-p and h the alloys containing hydrogen (x = 0 .…”