Energy distribution curve

Figure 5.2 The modification of the electron energy distribution curve by the presence of diffraction limits in a crystal. The lower filled band is separated from upper unoccupied states in a semiconductor by a small energy difference, so that some electrons can be promoted to conduction by an increase in temperature...

Consider a distribution system that consists of a gaseous mobile phase and a liquid stationary phase. As the temperature is raised the energy distribution curve in the gas moves to embrace a higher range of energies. Thus, if the column temperature is increased, an increasing number of the solute molecules in the stationary phase will randomly acquire sufficient energy (Ea) to leave the stationary phase and enter the... 

Figure 10. Energy distribution curves of photoelectrons (EDCs) excited by AlKa radiation. The curves (a), (b), and (c) were obtained after the same sputtering as in Figure 9. (Reprinted from Ref [171], 2002, with permission from Elsevier.)...

Figure 3. ARUPS energy distribution curves taken with Hel radiation at normal incidence and an electron emission angle of 52" shown as a function of copper coverage. The intensity of the various curves has been normalized at the Fermi level Ef The individual curves are matched to their corresponding copper coverages in monolayers by the solid lines and the saturation behavior of the interface state at approximately —1.5 eV is identified by the dashed lines. (Data from ref. 8.) (Reprinted with permission from ref. 43. Copyright 1987 American Association for the Advancement of Science.)...

Example The thermal energy distribution curves for 1,2-diphenylethane, C14H14, 5 = 3 X 28 - 6 = 78, have been calculated at 75 and 200 °C. [34] Their maxima were obtained at about 0.3 and 0.6 eV, respectively, with almost no molecules reaching beyond twice that energy of maximum probability. At 200 °C, the most probable energy roughly corresponds to 0.008 eV per vibrational degree of freedom. 

Fig. 15. Angle-integrated photoelectron energy distribution curves of uranium in the region of the giant 5 d -> 5 f resonance (90 eV < hv < 108 eV). The 5 f intensity at Ep is suppressed by more than a factor of 30 at the 5 ds/2 threshold (see the spectra for hv = 92 and 94 eV) and resonantly enhanced above threshold (see, e.g., the spectrum for hv = 99 e V). At an initial energy 2.3eV below Ep a new satellite structure is observed which is resonantly enhanced at the 5 d5/2 and 5 ds onsets. At threshold the satellite coincides with the Auger electron spectrum, which moves to apparently larger initial energies with increasing photon energy (from Ref. 67)...

A typical energy distribution curve is represented by Fig. 3. An elec-... 

Hence the energy difference ICH2 - C = 8.5 kcal/mol is obtained. The energy distribution curve of the fragments at 308 nm has only one peak suggesting only I-CH2 is produced. 

This third primary process produced the hydroxymethyl radical which was needed to explain the third low energy peak in the translational energy distribution curve. From the areas associated with each of the peaks in the translational distribution curves they were able to determine that the relative quantum yields for each of these primary process were 9,4,1, and respectively, for reactions 19, 20, and 21. 

The center of mass (CM) translational energy distribution curve (P(Ef) versus Erp) derived from T0F measurements of the Br atom produced in the 193 nm photolysis of bromoacetylene has three peaks. They occur at Erj, of 75, 40, and <20 kJ/mol. The first two peaks have about the energy difference associated with the spin-multiplet splitting in Br and suggest that the following primary processes occur at 193 nm ... 

For samples in good ohmic contact to the detector system the photoelectron energy distribution curve is referred to the Fermi level Ef. Adsorbate induced shifts of the photoemission spectra are thus related to changes of the binding energy values EB and changes of the work function Eg= hv - Efcin - 41 and Acft = - eVbb +... 

Two variables of a PES experiment are readily altered the input photon energy (hv) and the output photoelectron kinetic energy (KE). In a classical energy distribution curve (EDC) operation mode, one scans KE only and obtains information on the energy level manifold. While this is the only mode possible with fixed-energy VUV photon sources, SR permits two further combinations a constant final-state (CFS) mode where one scans hv and a constant initial-state (CIS) mode with both hv and KE scanned in such a way that their difference remains constant. CIS and CFS modes permit separate studies of the initial (ground electronic states, ionization probabilities) and final (photoelectron perturbed by the molecular ion) stages of photoionization events. 

Fig. 5. Energy distribution curves at a photon energy of 30 eV for three different conditions (a) after a-Si deposition (b) after H2 exposure at 10 2 Torr for 2 min (c) after 02 exposure at 5 X 10 5 Torr for 7 min at 110°C. The tops of valence tend of SiOx and a-Si H are also extrapolated (dashed lines). The top of SiO, VB shifts from 2.7 e V under the Fermi level to 2.45 eV (AE = 0.25 eV), while the top of a-Si H shifts from 0.6 to 0.35 eV, going from condition (b) to condition (c).

That conclusion is further evidenced if we consider two typical equilibrium energy-distribution curves for identical systems at two different temperatures (Fig. X.l). Here P E) dE represents the fraction of mole-... 

Figure I shows representative energy distribution curves (EDCs) for Cso taken at Av 65, 170, and 1486.6 eV additional spectra acquired from 20 to 200 eV in 2-eV increments will be discussed elsewhere. Figure 2 shows an EDC acquired at 50 eV with an experimental resolution of 0.2 eV. The zero of energy is the emission maximum of the highest occupied feature. Calculations for neutral C6o, Cso, and C6o indicate that the removal or addition of one electron would displace these levels rigidly. With account of the position the Fermi level...

Figure 7 Ni(100)c(2 > 2)-S. (a) UPS energy distribution curves solid line, theory for S in fourfold hollow dashed line, theory of S in "atop position full points, experimental. (b) Polar intensity plots...

Figure 10 Ni(100)c(2 x 2)-Se. Relative Se 3d photoemission energy distribution curve, with calculated peak energies indicated for the atop and fourfold hollow adsorption sites (Reproduced by permission from Phys. Rev. Letters, 1978, 41, 1565)...

We note that the work function increases upon CHC1, chemisorption for silver and copper clusters. The work-function change is monitored by the change in width of the photoelectron energy distribution curve (Table II). We find an increase in work... 

The occupied states are derived from energy distribution curves of the photoelectrons, excited by synchrotron illumination. We present XPS spectra at resonant excitation energies at the Cls (285 eV), and at the S2p (165 eV) ionisation thresholds. For the Cls threshold, we in addition show the spectrum taken off resonance. These valence band spectra are dominated by two broad features at -7 eV and -11.5 eV which are due to carbon-derived (//c) and sulfur-derived (//s) HOMOs of the thiophene monomer. These levels are pronounced in all data, as marked by the dashed lines. The weaker emission of the highest band at -3.1 eV is attributed to emission from electrons out of the 71-band, which is no longer assigned to individual monomers but is delocalised along the polymeric chain see also [33]. 

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