Shake-up satellites are found in the resonant inelastic x-ray scattering spectra of CuO single crystals, excited by means of monochromatized synchrotron radiation with energies near the Cu K-edge. Within the limits of third-order perturbation treatment, the satellites are attributed to charge transfer excitations between a bonding b 1g ground state and antibonding states of a 1g , b 2g , b 1g , and e g symmetry. These transitions are induced by Coulomb interaction of the 1s គ-hole, which constitutes the intermediate state of the resonant inelastic x-ray scattering process, with the Cu 3d system. We have modeled the dependence of the satellite's energy loss position on the incident photon energy by means of a third-order perturbation treatment, where two different Cu 1s គ3d 9 4p excitations constituting the resonant inelastic x-ray scattering process must be taken into account. Together with a dipole forbidden 1s គ3d 10 and a dipole allowed 1s គ3d 10 L គ4p transition, another dipole allowed Cu 1s គ3d 9 4p excitation was investigated in detail by means of resonantly excited 1s គ2p ͑K ␣ ͒ emission, especially with respect to its dependence on incident polarization. Since this excitation does not leave behind a trace in conventional x-ray absorption spectra, symmetry assignment can be obtained only this way. An investigation of the dependence of the satellite's intensity on the scattering angle in vertical and horizontal scattering geometry has stressed the necessity to take into account the polarization and scattering angle dependence of the resonant elastic scattering process, being composed of the production and recombination of the virtual 1s គ4p exciton, when it is regarded to be decoupled from the Cu 3d system.

We present temperature-dependent valence Compton profiles of single-crystalline Al and Li measured with 30 keV incident energy and 173°scattering angle with momentum space resolution of 0.1 a.u. The valence profiles for both samples measured at low temperature are above the high-temperature ones at momentum p z Ϸp F , the Fermi momentum, and below at p z ϭ0 a.u., which corresponds to a narrowing of the valence Compton profiles with increasing temperature. This fundamental temperature dependence can be attributed to the variation of the lattice constant and thus the variation of the Fermi momentum with temperature when the experimental results are compared with jellium calculations of the valence Compton profiles utilizing a correlation corrected occupation number density. In addition the Li experiment shows a significant temperature dependence even for p z Ͼp F , which is assigned to the diminished contribution of higher momentum components to the valence Compton profile with increasing temperature. The Li results are in good agreement with calculations using an empirical temperature-dependent local pseudopotential.

We present Compton profiles ͑CP's͒ of Li measured with momentum space resolution of 0.02 a.u. and 8-9 keV incident photon energy. The valence CP's are found to be asymmetric in shape and the predicted sharp features at the Fermi break are drastically smeared out. The observed additional broadening of the CP beyond experimental resolution is predominantly attributed to the finite width of the spectral density function of the excited particle. The asymmetry agrees well with calculations using a many-particle scheme, which will be useful for interpreting final states in soft x-ray and photoemission. RAPID COMMUNICATIONS R7690PRB 62 C. STERNEMANN et al.

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