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Energy width

Figure Bl.24.5. Backscattering spectrum of a thin Ni film (950 A) with near monolayers ( 30 x 10 at cm of An on the front and back surfaces of the Ni film. The signals from the front and back layers of An are shown and are separated in energy from each other by nearly the same energy width as the Ni signal. Figure Bl.24.5. Backscattering spectrum of a thin Ni film (950 A) with near monolayers ( 30 x 10 at cm of An on the front and back surfaces of the Ni film. The signals from the front and back layers of An are shown and are separated in energy from each other by nearly the same energy width as the Ni signal.
Figure Bl.26.22. The energy width W of an ultraviolet photoelectron spectrum from a solid may be used to detemiine the work fimction. Changes in work fimction may be obtained from changes in the cut-off of the secondary electron peak (inset) (Attard G and Bames C 1988 Surfaces (Oxford Oxford University Press)). Figure Bl.26.22. The energy width W of an ultraviolet photoelectron spectrum from a solid may be used to detemiine the work fimction. Changes in work fimction may be obtained from changes in the cut-off of the secondary electron peak (inset) (Attard G and Bames C 1988 Surfaces (Oxford Oxford University Press)).
Moiseyev N 1998 Quantum theory of resonances calculating energies, widths and cross-sections by complex scaling Rhys. Rep. 302 212... [Pg.2323]

In principle, energy-analyzer systems can be designed such that their electron-optical properties do not limit the energy resolution attainable, i. e. their intrinsic energy resolution is much better than the energy width of the primary electron beam, which is of the order of approximately 1.5-2.5 eV for a tungsten hairpin cathode, approximately 1 eV for a LaBg cathode, approximately 0.7 eV for a Schottky field emitter, and 0.3-0.5 eV for a pure cold-field emitter. [Pg.54]

Of course, the distinction between reactive- and bound-state wave functions becomes blurred when one considers very long-lived reactive resonances, of the sort considered in Section IV.B, which contain Feynman paths that loop many times around the CL Such a resonance, which will have a very narrow energy width, will behave almost like a bound-state wave function when mapped onto the double space, since e will be almost equal to Fo - The effect of the GP boundary condition would be therefore simply to shift the energies and permitted nodal structures of the resonances, as in a bound-state function. For short-lived resonances, however, Te and To will differ, since they will describe the different decay dynamics produced by the even and odd n Feynman paths separating them will therefore reveal how this dynamics is changed by the GP. The same is true for resonances which are long lived, but which are trapped in a region of space that does not encircle the Cl, so that the decay dynamics involves just a few Feynman loops around the CL... [Pg.38]

If the energy difference AE is chosen to be the energy width 8E of a single channel in the multichannel analyser, then each channel corresponds to a thickness 8z ... [Pg.93]

TABLE I. Energies, widths, and oscillator strengths for one- and two-photon absorption in polydiacetylene solutions (energies and widths in cm-l). [Pg.206]

The energy width A is typically of the order of 1 eV we treat it as a parameter and perform calculations for a few representative values. [Pg.256]

Resonance Energies, Widths, and Wave Functions Using a Lanczos Method in Real Arithmetic. [Pg.342]

Figure 2 The photoabsorption (c), photoionization (o-,-), and photodissociation (cr Figure 2 The photoabsorption (c), photoionization (o-,-), and photodissociation (cr<j) cross sections of CH4 as a function of the incident photon energy measured via the double ionization chamber and synchrotron radiation as mentioned in Section 2.1. The values of cr in the range below the first ionization potential were measured by the photon-beam attenuation method, using the ionization chamber as a conventional gas cell. The bandpass was 0.1 nm, which corresponds to the energy width of 32 meV at the incident photon energy of 20 eV. The vertical ionization potentials of the ionic states involved are also indicated by the vertical bars [11]. (From Ref [7]. Reprinted with permission from Flsevier Science.)...
The measured half-life of the state is 89.4 ps, which corresponds to a energy width, T, or AE, due to the Heisenberg uncertainty principle of ... [Pg.242]

By condition 3 we want to ensure that the Born-Oppenheimer approximation can be applied to the description of the simple systems, allowing definition of adiabatic potential-energy curves for the different electronic states of the systems. Since the initial-state potential curve K (f ) (dissociating to A + B) lies in the continuum of the potential curve K+(/ ) (dissociation to A + B + ), spontaneous transitions K ( )->K+(f ) + e" will generally occur. Within the Born-Oppenheimer approximation the corresponding transition rate W(R)—or energy width T( ) = hW(R) of V (R)... [Pg.403]

The final method which is proving of value is the gas-cell technique, in which use is made of the natural peaking of the positronium formation cross section in the direction of the incident positrons (see Chapter 4 for further discussion of this feature) for the reaction described by equation (1.12). This method was pioneered independently by Brown (1985, 1986), and by Laricchia and Charlton and coworkers (Laricchia et al., 1986, 1987b, 1988), who have shown that a tunable positronium beam with narrow energy width can be produced by the capture reaction in gases. Further discussion of this technique, and some applications in atomic physics, can be found in section 7.6. [Pg.34]

It was found that the boron target itself acted as a moderator with a low efficiency of 10-7, but the emitted positrons had a low energy, and therefore a narrow energy width, of approximately 0.1 eV. [Pg.51]

In addition to the work on atoms, the study of Katayama, Sueoka and Mori (1987) produced cross sections attributable to excitation of the O2 molecule by positron impact. The TOF apparatus and the method of analysis were similar to those described above. However, for O2 a secondary peak was found which, when allowances were made for the energy width of the beam and for positrons which had been scattered through large angles, was concentrated in an energy-loss interval AE ... [Pg.225]

The first hints that the energy dependence of a + near E was different for positrons and electrons came from the results of Fromme et al. (1986, 1988) for helium and molecular hydrogen, which revealed that energy dependence than <7+(e ) and that the former falls below the latter very close to E. This type of behaviour is consistent with the expected Wannier laws for the two projectiles, though the energy width of the positron beam and other instrumental effects (see section 4.3 for a discussion of the operation of the ion extractor in this experiment) meant that the measurements were insufficiently precise for a value of the exponent to be extracted. [Pg.247]

Conversely, a coherent superposition of continuum states with a population closely reproducing an isolated peak in the density of states, which corresponds to a resonance, can be built in such a way to give rise to a localized state. From this localized state, there will be an outward probability density flux, i.e., it will have a finite lifetime. In the limit of a resonance position far from any ionization threshold and a narrow energy width, the decay rate will be exponential with the rate constant T/ft. The decay is to all the available open channels, in proportion to their partial widths. [Pg.252]


See other pages where Energy width is mentioned: [Pg.1309]    [Pg.1833]    [Pg.1836]    [Pg.1893]    [Pg.77]    [Pg.330]    [Pg.479]    [Pg.481]    [Pg.647]    [Pg.57]    [Pg.63]    [Pg.473]    [Pg.287]    [Pg.217]    [Pg.238]    [Pg.63]    [Pg.210]    [Pg.781]    [Pg.242]    [Pg.369]    [Pg.5]    [Pg.11]    [Pg.21]    [Pg.53]    [Pg.134]    [Pg.237]    [Pg.27]    [Pg.52]    [Pg.128]    [Pg.254]   
See also in sourсe #XX -- [ Pg.63 , Pg.76 ]




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