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The ultrafast electron and spin dynamics of Co films was investigated using a femto-second pump-probe technique. The samples were magnetically characterized by means of magnetooptical Kerr effect and non-optical magnetometers, i.e. superconductive quantum interference device and alternating gradient field magnetometer. Time evolution of both, Kerr rotation and ellipticity, was measured at different points of the static hysteresis cycle. This allowed separating magnetic and non-magnetic contributions to the signal. The sample magnetization was found to drop within 200 fs, following the pulse cross-correlation trace, while the magnetization recovery time was found to last few picoseconds.

A total quenching of the charge transfer related emission is observed in the 3s photoelectron spectra of NiO single crystals taken at hν=180 eV photon energy. This finding is related to an efficient screening mechanism of the 3s core hole which prevents the stabilization of charge transfer derived configurations in the final state of the photoemission process, leading to a spectrum with the lone high and low-spin exchange components.

A study of multi-electron excitations in the O 1s X-ray photoemission (XP) region of NiO single crystal is reported. The observed spectral lines are discussed and assigned to surface and bulk plasmon losses on the basis of a Kramers-Kronig analysis of the 0–30 eV range reflectivity data. These results, in agreement with former and present optical studies and electron energy loss data, show for the first time, that the bulk and surface plasmon losses are well detectable, until the third order, in the XP spectra of high quality NiO single crystals.

The electronic structure of a Bi2CuO4 single crystal is studied by means of Electron Energy Loss Spectroscopy (EELS), at two primary beam energies (200 eV and 2 keV). The valence and shallow core electron excitation regions are investigated and the detected spectral features assigned, also exploiting the two different probing depths. Beside these results, the accidental loss of oxygen induced by a relatively long exposure of the sample to UV and X radiation, with the subsequent recovery of the oxygen stoichiometry, by exposing the crystal to oxygen atmosphere, allow to identify unambiguously some features in the EEL spectrum of this compound. It is proposed that the loss at 3.6 eV, seen in some cuprates, is not detected in Bi2CuO4 because it corresponds to an excitation involving the apical oxygens, not present in this compound.

We report off-normal angle-resolved photoemission data from NiO(001), which is complementary to the earlier normal-emission result. On the one hand, the energy position of the bands along this direction and the dispersion of the lowest oxygen band agree with the band calculation very well. On the other hand, the existence of the valence band satellite and the absence of the energy band in the gap region do not agree with the band calculation. For the first time, interesting movement of the Ni d7 satellite has been observed as a function of the emission angle and the photon energy, which is most likely a result of the satellite dispersion.

A new optical absorption band in small metal clusters is predicted and studied. It might be due to resonance of free electrons confined inside the metal clusters. The model attempts to explain some anomalous absorption peaks in the infrared absorption spectra of fine metal particles.

The room temperature absorption, in the threshold region of single crystals of K 2 CoF 4 , Rb 2 CoF 4 , K 2 NiF 4 was measured. Synchrotron radiation was used as continuum light source. The threshold is attributed to electron orbital promotion transitions 3 d n a 3 d n −1 (4 s , 4 p ) 1 of 3 d metal ions. Crystals reflectivity was measured in the 8–35 eV region. It is shown that all the optical structures are associated only with transitions of the alkali and halide electrons.