Spectra x-ray photoelectron

This point is illustrated in Figure 8.13 which shows the X-ray photoelectron spectrum of a 2 1 mixture of CO and CO2 gases obtained with MgXa (1253.7 eV) source radiation. The ionization energy for removal of an electron from the s orbital on a carbon atom, referred to as the C s ionization energy, is 295.8 eV in CO and 297.8 eV in CO2, these being quite comfortably resolved. The O s ionization energy is 541.1 eV in CO and 539.8 eV in CO2, which are also resolved. 

Figure 8.14 The monochromatized AlATa carbon Is X-ray photoelectron spectrum of ethyltrifluoroacetate showing the chemical shifts relative to an ionization energy of 291.2 eV (Reproduced, with permission, from Gelius, U., Basilier, E., Svensson, S., Bergmark, T. and Siegbahn, K., J. Electron Spectrosc., 2, 405, 1974)...

Figure 8.18 shows an X-ray photoelectron spectrum of gold foil with mercury absorbed onto the surface. Both the gold and mercury doublets result from the removal of a 4/ electron leaving /2 and /2 core states for which L = 3, S = and J = or Less than 0.1 per cent of a monolayer of mercury on a gold surface can be detected in this way. 

In Figure 8.19 is shown the X-ray photoelectron spectrum of Cu, Pd and a 60 per cent Cu and 40 per cent Pd alloy (having a face-centred cubic lattice). In the Cu spectrum one of the peaks due to the removal of a 2p core electron, the one resulting from the creation of a /2 core state, is shown (the one resulting from the 1/2 state is outside the range of the figure). 

Figure 8.25 shows the AXn,m. ii,iii Auger spectrum of a gaseous mixture of SFe, SO2 and OCS, all clearly resolved. The three intense peaks are due to sulphur in a >2 core state, but there are three weak peaks due to a core state also. The S 2p X-ray photoelectron spectrum of a mixture of the same gases is shown for comparison, each of the three doublets being due to sulphur in a 1/2 or 3/2 core state. 

The X-ray photoelectron spectrum of the core ionization of an atom in a molecule consists of peaks and bands corresponding to transitions to various excited states. None of these transitions corresponds to the formation of the Koopmans theorem frozen-orbital ionic state, which is a completely hypothetical state. However, the center of gravity of the various peaks and bands lies at the energy corresponding... 

Fig. 2. The Ols and C 1 s regions of the X-ray photoelectron spectrum of C3O2, showing the shake-up satellites. Reproduced with permission from Ref.77)...

Figure 2. High-resolution X-ray photoelectron spectrum of naturally weathered galena, PbS, in the sulfur 2p-j/2(l/2 re8i°n ...

Figure 2. X-ray photoelectron spectrum (Al 2s1/%) of BTDA + m,m -DABP + Al(acac)3 polymer film (B.E. = 118.4 eV)...

Chen, J., Lian, J., Wang, L. M., Ewing, R. C., Farmer, J. M. Boatner, L. A. 2002. Structural alterations in titanate pyrochlores induced by ion irradiation X-ray photoelectron spectrum... 

Further evidence is the x-ray photoelectron spectrum of the catalyst, which is about the same whether the reduction is carried out in CO or in ethylene (30). However, more positive evidence comes from Baker and Carrick (32) who measured the valence on a catalyst exposed to ethylene at 125°C, a typical polymerization temperature. Within a few minutes they obtained 85-96% conversion to Cr(II). Formaldehyde was the by-product. 

Figure 27-11 Carbon 1s x-ray photoelectron spectrum of ethyl trifluoro-ethanoate. The zero point is 291.2 eV. (Kindly supplied by Professor K. Siegbahn.)...

A typical x-ray photoelectron spectrum consists of a plot of the intensity of photoelectrons as a function of electron EB or E A sample is shown in Figure 8 for Ag (21). In this spectrum, discrete photoelectron responses from the core and valence electron eneigy levels of the Ag atoms are observed. These electrons are superimposed on a significant background from the Bremsstrahlung radiation inherent in nonmonochromatic x-ray sources (see below) which produces an increasing number of photoelectrons as EK decreases. Also observed in the spectrum are lines due to x-ray excited Auger electrons. 

Fig. 10 X-ray photoelectron spectrum (S 2p region) of LDPE after UV irradiation in the presence of S02 and air (.). Experimental data (...) Gaussian fits for the S 2p3/2 and S 2p1/2 peaks with maxima at 169.2 and 170.6 eV...

In this section we shall particularly study the dynamic properties of a core hole in terms of its self-energy and spectral function15 19,23,27 32). This is a kind of model problem because one does not discuss by which physical mechanism the core hole is created. The hole is simply created in the system at a specific instant of time and destroyed at a later time. By studying the development of the core hole during this interval one gets a picture of how the core level strength becomes distributed over the various possible levels of the ionic system. Nevertheless, since the creation of the core hole is sudden, the resulting spectral function is very closely connected to the X-ray photoelectron spectrum (XPS) as already briefly discussed in Sect. 2.2, Eq. (6). 

So far, we have fairly extensively discussed the general aspects of static and dynamic relaxation of core holes. We have also discussed in detail methods for calculating the selfenergy (E). Knowing the self-energy, we know the spectral density of states function A (E) (Eq. (10)) which describes the X-ray photoelectron spectrum (XPS) in the sudden limit of very high photoelectron kinetic energy (Eq. (6)). We will now present numerical results for i(E) and Aj(E) and compare these with experimental XPS spectra and we will find many situations where atomic core holes behave in very unconventional ways. 

Fig. 24. X-ray photoelectron spectrum of EVA-DAS film grafted with glycol chitosan...

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