Satellite intensities

The transition-metal and rare-earth core-line XPS spectra show little, if any, BE shifts at all. Nevertheless, information about atomic charge and valence states can be extracted by examining other features in the spectra. The plasmon loss satellite intensity found in the spectra of Co-containing compounds provides a particularly useful handle on the Co charge. The lineshapes of RE spectra are characteristic of their valence state, as seen in the distinction between trivalent and tetravalent cerium in CeFe4Pni2 compounds. 

The Co 2p XPS spectra from in situ treatments of the catalysts are shown in Figures 2-5. The Co 2p BE, line shape, and satellite intensity vary noticeably among the samples. The variation of these three spectral features has been shown to be useful in identifying the different Co species present in a sample (4). For the Co V /2 line> the metallic peak is located near 778 eV, the +2 and +3 oxide peaks are near 781 eV, and +2 satellite peak is near 787 eV. The Co V /2 features are located at 15-16 eV higher BE than the corresponding Co V /2 peaks. 

The relative instrumental sensitivity factors for cobalt and nitrogen were determined by measuring core level (Co 2p and N Is) XPS spectra for a series of pure cobalt amine complexes of established stoichiometry. To evaluate the core level photopeak intensities, peak areas, including shake-up satellite intensity were used. The precision for the measurements of the nitrogen to cobalt atomic ratio is 10% while the accuracy is approximately 15%. Additional details of the XPS measurements are contained in the literature (24,25). 

Energy dependent UPS data , together with XPS results, support this description the satellite intensity becomes less pronounced compared with the 5 f emission at Ep... 

Table 4. Nearest interatomic U-U spacings, effective paramagnetic moments, and estimated 7 eV XPS satellite intensities for various binary uranium compounds (from Ref. 122). The references for the intensities and distances are given in ...

If there is alignment, contrast in TEM images is strong, because of the periodic strain field in the crystal. Selected-area diffraction shows evidence of such alignment by the location of satellite intensities around the Bragg peaks arising from the modulation of atomic scattering factors, lattice constant, or both [19]. In Fig. 18.10, the electron diffraction effects, expected from an f.c.c. crystal with (100) composition waves, are depicted with a [001] beam direction. 

Figure 5.5 Relative intensities of xenon photosatellites as functions of photon energy, in the region of 4d - np excitations (a) 4d105s25p4(1S0)7p 2P° satellite (b) 4d105s25p4(1S0)8p 2P° satellite. The energy positions of 4d5/2 - np excitations are indicated by the vertical lines, numbered n = 7,8,9,.... For a detailed explanation of the effect that these resonance excitations have on the satellite intensities see main text for a related study see [BSK89b].

We determined Tc for films of various thickness by analyzing the T dependence of both the out-of-plane lattice parameter [4] and the satellite intensity [5], The latter method was more accurate for ultrathin films, where the finite-size broadening of the Bragg peaks becomes severe. The values of Tr (d) obtained are shown in Figure 8.7 (b). For thicker films we observe that Tc approaches the predicted value of 752°C for coherently strained PbTiC>3 on SrTiC>3 as d — oo. As <7 decreases, Tc is gradually suppressed by hundreds of degrees below... 

Figure 14.6 Evolution of the KL23L23 satellite intensities in (a) Cu and (b) Ni metals, related to the intensity of the ]D2 main Auger line (Sat 1 final-state shake up Sat 2 initial-state shake up), as a function of the excess photon energy above the K-absorption threshold [17]. For comparison, the predictions of the Thomas model [21] and the generic model [17] are also indicated.

Fig. 17. Vibronic coupling mechanisms (Herzberg-Teller couplings). The purely electronic transition between the excited state I (triplet substate) and the ground state 0 (Sq) is spin and symmetry forbidden, i.e. no intensity is found at the electronic origin I. Two mechanism are proposed. Coupling route (a) is probably more important for vibrations of metal-ligand character, while mechanism (b) preferentially induces satellite intensities by internal ligand vibrations. The electronic state S is a singlet, for which an electronic transition is dipole forbidden to the electronic ground state Sq. On the other hand, the state S , represents a singlet that carries sufficient transition probability. For detailed explanations see the text...

The potential of the SW approach to systematize inneratomic properties and processes can be easily illustrated by reconsidering chemically induced nuclear lifetime variations which, among others, are of relevance to the calibration problem of Moessbauer isomer shifts. Highly excited atom states carrying single or multiple vacancies in inner shells form another promising subject of SW simulations. In the latter case the results of a DV-Xa study of the K-shell x-ray satellite intensities of metal fluorides can be used for a comparative assessment of both methods. 

In photoelectron. Auger and X-ray spectroscopies, the frozen core and sudden approximations have frequently been used for their simplicity. However, interesting chemical bond effects in Auger and X-ray spectra have not yet been explained by such over simplified approximations. The representatives are remarkable changes in satellite intensity distributions appeared in X-ray and Auger spectra emitted from a series of fluorides [14-20], Introduction of a new concept of... 

Next we discuss the change in the fluorescence yields for the doubly ionized states, in order to explain the chemical bond effects in the satellite intensities of XI lines in the F Ka fluorescent X-ray spectra. Here we assumed that the fluorescence yield is divided into two, i.e. one for the diagram lines of XO and A,... 

Calculated relative cross sections for Xl/XO with the aid of eqs. (7) and (8) are compared with the observed ones in Fig. 13. Agreement between experiments and calculations is satisfactory. This means that even on the ion induced F Ka X-ray spectra, ROR plays one of the most important role in the chemical bond effects on the XI satellite intensities. 

Satellite Intensity Distributions Written in the Atomic Frame... 

Fig. 4. Schematic spectra for observed (white) [9] and calculated (black) KlLn X-ray satellites. The incident ions were 1.4 MeV/amu C and O, and in the X-ray satellite intensity calculations the nuclear charges were assumed to be 6 and 8, respectively.

The present author proposed an the approximation method to explain the deviation of the X-ray satellite spectra intensity distributions from those described by eqs.(2),(5),(8) and (10), which we call Resonant Orbital Rearrangement (ROR) [6]. ROR was first used to explain the anomalous intensity distributions in F Ka satellite spectra which are emitted from a series of alkali-fluorides. Here resonance occurs during F Is ionization between the highest occupied molecular orbital (HOMO) in the KT. state and HOMO in the (K L +3s) state corresponding to the lowest unoccupied molecular orbital (LUMO) in the K L state. This leads to a reduction in the K L X-ray satellite intensity and to an increase in the K L X-ray diagram line intensity. Here (K L +3s) denotes the state with one vacancy in K shell and one vacancy in L shell and one electron in a 3s... 

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