No abstract

Direct quantitative correlations have been recently observed between the T-centre EPR signal and an optical absorption band at 370 nm, in X-irradiated YSZ, suggesting that the colour centre and the paramagnetic centre might be the same entity. In order to confirm this hypothesis, theoretical modeling was undertaken, where by appropriate refinement the known electronic structure of the T-centre is shown to be compatible with an optical transition, having an oscillator strength of the correct magnitude.

4 , VOCl3, and CrO2Cl2 are measured and interpreted with the help of ab initio CI calculations. The calculations are extended also to MnO3Cl and to the Cl 1s core excitation spectra of the whole series of molecules. The interpretation of the final excited states in terms of orbital composition is discussed, as well as the spectral variations along the series with the progressive substitution of the Cl atom by the O atom. -(FRONZONI*, G.; CORENO, M.; DE SIMONE, M.; FRANCESCHI, P.; FURLANI, C.; FURLAN, S.; PRINCE, K. C.; STENER, M.; DECLEVA, P.; Phys. Chem. Chem.

A new analysis of velocity distribution, optical photometry and X-ray surface brightness from ROSAT PSPC data of the galaxy cluster A 2319 is presented. The temperature profile derived from ASCA data (Markevitch 1996) is taken into account. A method to check the hydrostatic model in the presence of a temperature gradient is proposed. Consistency of the hydrostatic isothermal model and the explanation of the "β-discrepancy" are discussed. Galaxy and gas density profiles of the main component A 2319 A are derived, allowing for the effect of the secondary component A 2319 B. The inadequacy of a polytropic model, which would produce a binding mass decrease with respect to the isothermal β-model, is discussed. A simple interpolation of the temperature profile provides instead an increase of the binding mass and a lower baryon fraction thus mitigating the "baryon catastrophe". Assuming as typical the value f b ≈ 0.2, a comparison with the most recent estimate of Ω nucl b implies for the cosmological parameter Ω o ∼ < 0.4.

No abstract