No abstract

In electron beams with high charge density there are observed anomalous shiftings and broadenings as well as symmetrizations of the energy distribution (BoERSCa 1954). Continuing former work 1, where these phenomena were ascribed to a relaxation process changing the energy distribution to a new equilibrium distribution, quantitative expressions are derived for the energy spread and the shape of this new energy distribution. Furthermore a relaxation degree is defined which measures the progress of relaxation. Measurements are described with the highest relaxation degrees reached up to now. In addition to the verification of former results up to these new limits the shape of the measured energy-distributions can be fitted to the derived one with suitable choice of a single parameter. Peculiarities of measurements with superposed axial magnetic fields are discussed.

X-ray isochromats of Tantalum, Niobium and Tungsten for different temperatures are presented. They allow a localization of the Fermi edge in the conduction band and show, that the fine structure softens with increasing temperature. This is attributed to a change in the density of states in the conduction band. A modified rigid band model of the density of states for the bcc transition metals is constructed. It agrees well with our isochromats and with published calculations of the density of states for Tungsten. Other electronic properties also fit well into this model. In connection with the interpretation of our isochromats a short discussion of precision experiments for the evaluation of hie is added.

No 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.