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Atom scattering

An important simplification in the analysis of He scattering is the large mass mismatch between He and most other atoms that are the constituents of solid surfaces. Therefore, energy transfer between the He atom and the surface is very much limited and elastic He diffraction or inelastic He scattering can be modelled rather easily and quantum mechanically. The situation is very different when heavier atoms or molecules are scattered from a surface. In this case energy exchange between projectile and surface will be facile, and in most cases only classical mechanics can be used to model the interaction. Most of the [Pg.83]

A Flat surface, purely repulsive T i=oonst 1 1 C Corrugated surface + attractive welt aaAaaa  [Pg.84]

B Corrugated surface, purely repulsive 000000 a D Orientation dependent partially passivated wetl 1 Dqc  [Pg.84]

Molecular scattering at bare surfaces, angular distributions and energy transfer [Pg.85]

The effect of internal excitation on angular distributions and energy transfer will be discussed in a next section. Here it might be sufficient to state that the major part of the energy transfer is towards the lattice, and it that respect the influence of the internal degrees of freedom is not so large. [Pg.87]


The energies of the selective adsorption resonances are very sensitive to the details of the physisorption potential. Accurate measurement allied to computation of bound state energies can be used to obtain a very accurate quantitative fonn for the physisorption potential, as has been demonstrated for helium atom scattering. For molecules, we have... [Pg.903]

Vibrational spectroscopy provides detailed infonnation on both structure and dynamics of molecular species. Infrared (IR) and Raman spectroscopy are the most connnonly used methods, and will be covered in detail in this chapter. There exist other methods to obtain vibrational spectra, but those are somewhat more specialized and used less often. They are discussed in other chapters, and include inelastic neutron scattering (INS), helium atom scattering, electron energy loss spectroscopy (EELS), photoelectron spectroscopy, among others. [Pg.1149]

Figure Bl.8.1. The atomic scattering factor from a spherically synnnetric atom. The volume element is a ring subtending angle a with width da at radius r and thickness dr. Figure Bl.8.1. The atomic scattering factor from a spherically synnnetric atom. The volume element is a ring subtending angle a with width da at radius r and thickness dr.
Because the neutron has a magnetic moment, it has a similar interaction with the clouds of impaired d or f electrons in magnetic ions and this interaction is important in studies of magnetic materials. The magnetic analogue of the atomic scattering factor is also tabulated in the International Tables [3]. Neutrons also have direct interactions with atomic nuclei, whose mass is concentrated in a volume whose radius is of the order of... [Pg.1363]

The atomic scattering factor for electrons is somewhat more complicated. It is again a Fourier transfonn of a density of scattering matter, but, because the electron is a charged particle, it interacts with the nucleus as well as with the electron cloud. Thus p(r) in equation (B1.8.2h) is replaced by (p(r), the electrostatic potential of an electron situated at radius r from the nucleus. Under a range of conditions the electron scattering factor, y (0, can be represented in temis... [Pg.1363]

Equation (Bl.8.6) assumes that all unit cells really are identical and that the atoms are fixed hi their equilibrium positions. In real crystals at finite temperatures, however, atoms oscillate about their mean positions and also may be displaced from their average positions because of, for example, chemical inlioniogeneity. The effect of this is, to a first approximation, to modify the atomic scattering factor by a convolution of p(r) with a trivariate Gaussian density function, resulting in the multiplication ofy ([Pg.1366]

Potassium chloride actually has the same stnicture as sodium chloride, but, because the atomic scattering factors of potassium and chlorine are almost equal, the reflections with the indices all odd are extremely weak, and could easily have been missed in the early experiments. The zincblende fonn of zinc sulphide, by contrast, has the same pattern of all odd and all even indices, but the pattern of intensities is different. This pattern is consistent with a model that again has zinc atoms at the comers and tlie face centres, but the sulphur positions are displaced by a quarter of tlie body diagonal from the zinc positions. [Pg.1372]

A teclmique that employs principles similar to those of isomorphous replacement is multiple-wavelength anomalous diffraction (MAD) [27]. The expression for the atomic scattering factor in equation (B1.8.2h) is strictly accurate only if the x-ray wavelength is well away from any characteristic absorption edge of the element, in which case the atomic scattering factor is real and Filiki) = Fthkl V- Since the diffracted... [Pg.1377]

The major role of TOF-SARS and SARIS is as surface structure analysis teclmiques which are capable of probing the positions of all elements with an accuracy of <0.1 A. They are sensitive to short-range order, i.e. individual interatomic spacings that are <10 A. They provide a direct measure of the interatomic distances in the first and subsurface layers and a measure of surface periodicity in real space. One of its most important applications is the direct determination of hydrogen adsorption sites by recoiling spectrometry [12, 4T ]. Most other surface structure teclmiques do not detect hydrogen, with the possible exception of He atom scattering and vibrational spectroscopy. [Pg.1823]

Figure 4 Interference pettern created when regularly spaced atoms scatter an incident plane wave. A spherical wave emanates from each atom diffracted beams form at the directions of constructive interference between these waves. The mirror reflection—the (00) beam—and the first- and second-order diffracted beams are shown. Figure 4 Interference pettern created when regularly spaced atoms scatter an incident plane wave. A spherical wave emanates from each atom diffracted beams form at the directions of constructive interference between these waves. The mirror reflection—the (00) beam—and the first- and second-order diffracted beams are shown.
The Calculation and Interpretation of X-ray Term Values, and the Calculation of Atomic Scattering Factors... [Pg.709]


See other pages where Atom scattering is mentioned: [Pg.1362]    [Pg.1362]    [Pg.1364]    [Pg.1366]    [Pg.1367]    [Pg.1371]    [Pg.1373]    [Pg.1377]    [Pg.1629]    [Pg.1800]    [Pg.1803]    [Pg.1820]    [Pg.1824]    [Pg.2003]    [Pg.2457]    [Pg.366]    [Pg.334]    [Pg.518]    [Pg.19]    [Pg.36]    [Pg.103]    [Pg.196]    [Pg.236]    [Pg.249]    [Pg.265]    [Pg.506]    [Pg.769]    [Pg.79]    [Pg.209]    [Pg.65]    [Pg.22]    [Pg.474]    [Pg.458]    [Pg.627]    [Pg.673]    [Pg.712]    [Pg.731]   
See also in sourсe #XX -- [ Pg.83 ]




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Alkali halides helium atom scattering

Alkali-metal atoms scattering experiments

Amorphous atomic scattering amplitude

Anisotropic Atomic scattering factors

Aspherical atom scattering factor

Atom surface scattering cross

Atom surface scattering cross section

Atom-Surface Scattering, Kinematics

Atom-diatom scattering

Atom-molecule scattering

Atom-single-phonon scattering, inelastic

Atom-surface scattering

Atom-surface scattering accurate calculations

Atom-surface scattering calculations

Atom-surface scattering theory, helium

Atomic Scattering and Diffraction

Atomic adsorption/desorption/scattering

Atomic diffraction scattering

Atomic orbital probability scattering

Atomic scattering

Atomic scattering factor

Atomic scattering factor table

Atomic scattering factors for

Atomic scattering function

Atomic scattering technique

Atomic theory Rutherford’s scattering experiment

Atomic-beam surface scattering

Atoms Bragg scattering

Atoms scattering cross sections

Atoms scattering power

Bijvoet anomalous scattering, heavy atoms

Coherent forward scattering atomic

Coherent forward scattering atomic spectrometry

Cold atom scattering

Crossing resonances, helium atom scattering

Crystallographic techniques atomic scattering factor

Electron-atom scattering

Electron-atom scattering excitation

Electron-atom scattering ionization

Electron-atom scattering total cross sections

Energy transfer helium atom scattering

He-atom scattering (HAS)

Helium atom scattering

Helium atom scattering , metallic

Helium atom scattering lattice vibrations

Helium atom scattering metallic surfaces

Helium atom scattering surface dynamics

Helium atom scattering technique

Helium atomic scattering

Inelastic neutral atom scattering

Inelastic scattering of He-atoms

Laser-assisted electron-atom scattering

Localized atomic scattering

Modified spherical scattering factor for the hydrogen atom

Multiple scattering theory atomic cell

Open Shell Atomic Beam Scattering and the Spin Orbit Dependence of Potential Energy Surfaces

Phase relations (different atoms anomalous scattering

Phonons atom-multiphonon scattering

Phonons atom-single-phonon scattering

Proton-atom scattering

Quasielastic helium atom scattering

Reactive scattering, atom-diatom

Reactive scattering, atom-diatom approach

Scattering Amplitude for an Atom

Scattering atomic absorption spectroscopy

Scattering by Molecules Independent Atom Approximation

Scattering by a multi-electron atom

Scattering by an atom

Scattering cross section Bound atom

Scattering cross section Single atom

Scattering from atoms

Scattering length bound-atom

Scattering length free-atom

Scattering mean square atomic

Scattering power of atoms

Shape Resonances in Atom and Molecule Scattering

Simple Models for Atom-Surface Scattering

Single atom scattering

Single atom scattering theory

Surface phenomena atom scattering

Surface vibration helium atom scattering

The atomic scattering factor

Theory of atomic scattering

Thermal energy atom scattering

Thermal energy atom scattering (TEAS)

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