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AES spectra

In Ae hydrogen TPD spectrum, Ae lower-temperature peak occurs at 355 K, characteristic of desorption of surface hyAogen Ni(lOO). Hence it is defined by Ae desorption kinetics... [Pg.329]

The variance may be adopted to evaluate the accuracy of the coupling scheme used. Indeed, its formula (32.21) consists of two terms, corresponding to spin-orbit and electrostatic interactions, therefore the quantity aso/ae may also serve as a measure to estimate the coupling scheme. It is preferred over the ratio rj i/F2(nl, nl), because the coupling scheme depends not only on radial integrals, but also on spin-angular parts of them. Let us also mention that a characterizes the width of the spectrum AE, i.e. the energy separation between upper and lower levels. [Pg.387]

Fig. 33. Ba 5p - 6s2ep (O23P1P1) electron-excited atomic Auger spectrum (AES)54-55) giving a direct picture of the 5 p hole spectrum (see text)... Fig. 33. Ba 5p - 6s2ep (O23P1P1) electron-excited atomic Auger spectrum (AES)54-55) giving a direct picture of the 5 p hole spectrum (see text)...
Fig. 2. Transient absorption spectrum (Ae = 420 nm) from MA and C o (2 x 10 M) containing biphenyl (0.2 M) in CH Cb Inset transient decay = 980 nm, average of 10 shots)... Fig. 2. Transient absorption spectrum (Ae = 420 nm) from MA and C o (2 x 10 M) containing biphenyl (0.2 M) in CH Cb Inset transient decay = 980 nm, average of 10 shots)...
Ribonuclease Acid versus neutral A-spectrum Ae versus pH abnormally steep Scheraga (1957)... [Pg.348]

Fig. 2. The axial single crystal circular dichroism spectrum (Ae/10) of 2 A-t+XCofenlslCls NaCl 6 H2O (solid curve) and the absorption and CD spectrum of A-(+)-[Co(en)3l(a04)3 in water (upper and lower broken curves, respectively). The axial crystal CD spectrum characterises electronic transitions of the complex ion to upper states of symmetry, polarized perpendicular to the threefold rotation axis of the complex... Fig. 2. The axial single crystal circular dichroism spectrum (Ae/10) of 2 A-t+XCofenlslCls NaCl 6 H2O (solid curve) and the absorption and CD spectrum of A-(+)-[Co(en)3l(a04)3 in water (upper and lower broken curves, respectively). The axial crystal CD spectrum characterises electronic transitions of the complex ion to upper states of symmetry, polarized perpendicular to the threefold rotation axis of the complex...
The small CD activity of the guest (lAsI <0.2) may be enhanced successfully to be detected easily as a readout in the CD spectrum (Ae -i-8.8) (chiroptical enhancement). This protocol was applied to the detection of a (-)-phenylephrine-H+ salt 3 (lAsI <0.2) to give an enhanced readout (Ae -i-9.6). For the anti-atropisomer (anti-1), no chiroptical signal was induced on the addition of (R,R)-2 or (-)-phenylephrine-H+ salt 3 due to a non-propeller-shaped structure. [Pg.251]

If em adsorbed molecule is moving in electronically adiabatic potential well the model of two-dimensional anharmonic oscillator can be used for the description of its vibrational spectrum. This spectrum E(,n) (n = (ni,Ti2)) can be calculated by the numerical or analytical integration of the two-dimensional Schrodinger equation. The calculations of the transition probabilities e E, E) (or e(n, n)) for such oscillator have been performed with the help of the pertiu-bation theory or more sophisticated approaches. Provided these transition probabiUties e(n, n) are known for dense enough energy spectrum (AE ksT ), a diffusion model of energy relaxation may be used... [Pg.42]

Figure 3. Brittle material AE responses as count velocity N and logarithm spectrum log (S) characteristics of the process... Figure 3. Brittle material AE responses as count velocity N and logarithm spectrum log (S) characteristics of the process...
Experimental. The vibrational spectrum of an ideal harmonic oscillator would consist of one line at frequency v corresponding to A = hv, where A is the distance between levels on the vertical energy axis in Fig. 10-la. In the harmonic oscillator, AE is the same for a transition from one energy level to an adjacent level. A selection rule An = 1, where n is the vibrational quantum number, requires that the transition be to an adjacent level. [Pg.301]

AES analysis is done in one of four modes of analysis. The simplest, most direct, and most often used mode of operation of an Auger spectrometer is the point analysis mode, in which the primary electron beam is positioned on the area of interest on the sample and an Auger survey spectrum is taken. The next most often used mode of analysis is the depth profiling mode. The additional feature in this mode is that an ion beam is directed onto the same area that is being Auger analyzed. The ion beam sputters material off the surface so that the analysis measures the variation, in depth, of the composition of the new surfaces, which are being continu-... [Pg.321]

Generally. 5j. In this way, a depth scale may be associated with an ERS spectrum, as shown in the schematic spectrum of Figure 3c. That spectrum shows the H recoil rate (counts per energy channel of width AE) as a function of E y and hence as a function of depth below the sample surface (see Equation (3)). [Pg.493]

The reasons AES is a surface-specific technique have been given in Sect. 2.1.1, with reference to Fig. 2.2. The normal range of kinetic energies recorded in an AES spectrum would typically be from 20 to 1000 eV, corresponding to inelastic mean free path values of 2 to 6 monolayers. [Pg.33]

Chemical effects are quite commonly observed in Auger spectra, but are difficult to interpret compared with those in XPS, because additional core levels are involved in the Auger process. Some examples of the changes to be seen in the KLL spectrum of carbon in different chemical environments are given in Fig. 2.24 [2.130]. Such spectra are typical components of data matrices (see Sect. 2.1.4.2) derived from AES depth profiles (see below). [Pg.38]

The relationship between what is recorded in a SSIMS spectrum and the chemical state of the surface is not as straightforward as in XPS and AES (Chap. 2). Because of the large number of molecular ions that occur in any SSIMS spectrum from a multi-component surface (e. g. during the study of a surface reaction), much chemical information is obviously available in SSIMS, potentially more than in XPS. The problem in using the information from a molecular ion lies in the uncertainty of knowing whether or not the molecule represents the surface composition. For some materials. [Pg.94]

Compared with XPS and AES, the higher surface specificity of SSIMS (1-2 mono-layers compared with 2-8 monolayers) can be useful for more precise determination of the chemistry of an outer surface. Although from details of the 01s spectrum, XPS could give the information that OH and oxide were present on a surface, and from the Cls spectrum that hydrocarbons and carbides were present, only SSIMS could be used to identify the particular hydroxide or hydrocarbons. In the growth of oxide films for different purposes (e.g. passivation or anodization), such information is valuable, because it provides a guide to the quality of the film and the nature of the growth process. [Pg.96]


See other pages where AES spectra is mentioned: [Pg.243]    [Pg.302]    [Pg.370]    [Pg.479]    [Pg.715]    [Pg.387]    [Pg.138]    [Pg.226]    [Pg.308]    [Pg.279]    [Pg.641]    [Pg.304]    [Pg.69]    [Pg.58]    [Pg.298]    [Pg.243]    [Pg.302]    [Pg.370]    [Pg.479]    [Pg.715]    [Pg.387]    [Pg.138]    [Pg.226]    [Pg.308]    [Pg.279]    [Pg.641]    [Pg.304]    [Pg.69]    [Pg.58]    [Pg.298]    [Pg.187]    [Pg.941]    [Pg.523]    [Pg.373]    [Pg.381]    [Pg.319]    [Pg.478]    [Pg.145]    [Pg.228]    [Pg.291]    [Pg.295]    [Pg.363]    [Pg.483]    [Pg.518]    [Pg.523]    [Pg.592]    [Pg.161]    [Pg.171]   
See also in sourсe #XX -- [ Pg.2 , Pg.3 ]




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AES

AES spectrum of a clean Ag surface

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