[en] We have analyzed the basic properties of Raman spectra of C₆₀ thin films and single crystals between room temperature and 10 K and studied the temperature-induced phase transition in this material. The photo-induced transformation of the crystals and its implication on the interpretation of the Raman spectra is discussed. The relative resonance Raman cross section has been measured. From a fit to the Albrecht theory optical transitions energies at 2.6 and 3.4 eV were deduced in good agreement with results from LDA calculations. Furthermore the luminescence of solid C₆₀ was investigated as a function of temperature. The experiments are described by a self-localized polaron exciton

[en] This paper is a study on the determination of the measurement uncertainty for a relatively simple and widespread calibration task. The measurement of a special form deviation of gauge blocks using the so-called five-point technique is discussed in detail. It is shown that the mainstream treatment of the measurement uncertainty (i.e. propagation of uncertainties) cannot be applied to this problem for principal reasons; the use of supplement 1 of the GUM (Monte Carlo method) is mandatory. The proposed model equation is probably the simplest ‘real world’ example where the use of supplement 1 of the GUM not only gives better results, but gives results at all. The model is simple enough to serve as a didactical example. Explicit analytical expressions for the probability density functions, expectation values, uncertainties and coverage intervals are given which is helpful for the validation of dedicated software products. Eventually a complete avoidance of the standardized form parameters in calibration certificates is proposed. The statement of ‘corner-deviations’ would be much more useful, especially for the evaluation of key comparisons. (paper)

[en] The Raman spectra of C₆₀ were investigated as a function of temperature and K-doping between 320 K and 10 K. Relationships between features in these spectra, the first order rotational phase transition at 260 K, and the higher order phase transition at 90 K are shown. For the doped fullerenes a strict phase separation between C₆₀, K₃C₆₀, and K₆C₆₀ was found. (orig.)

[en] Published in summary form only

[en] Published in summary form only

[en] IR measurements of Cu/Ga substituted 123-ceramics showed a reflectivity behavior which is characteristic for a superconducting gap along the c-direction in all details. Similar structures at higher energies in Cu/Ga substituted films did not show these features. Strong anomalies in phonon oscillator strength were observed in the ceramics at Tc for two modes at 157 and 190 cm^-1. (orig.)

[en] We have analysed the unusual light induced changes in the Raman spectra of C₆₀ single crystals and thin films. This changes revealed a strong dependence on the exposure of the material to ambient conditions. The changes are suppressed for temperatures above 80 C and for temperatures moderately below room temperature. Excitation to a triplet state and interaction with oxygen are considered as the main sources for the un unusual behavior of the spectra. (orig.)

[en] Tetragonal YBa₂ (Cu_o.90:0094GA_o.06)₃O_x ceramics were prepared for various X. Thus, it was possible to separate the tetragonal to orthorhombic phase transition from the metal to insulator transition. Structure, transport and Raman measurements are reported and compared to the system YBa₂CU₃O_x

[en] Published in summary form only

[en] Published in summary form only