Showing papers on "Scattering published in 1979"
01 Jan 1979
TL;DR: In this article, the authors discuss the principles of scattering in Hilbert space, quantum scattering, long range potentials, optical and acoustical scattering, the linear Boltzmann equation, nonlinear wave equations, spin wave scattering, quantum field scattering, and phase space analysis of scattering and spectral theory.
Abstract: Topics covered include: overview; classical particle scattering; principles of scattering in Hilbert space; quantum scattering; long range potentials; optical and acoustical scattering; the linear Boltzmann equation; nonlinear wave equations; spin wave scattering; quantum field scattering; and phase space analysis of scattering and spectral theory. (GHT)
1,179 citations
TL;DR: In this article, the doublefolding model was used to calculate the real part of the optical potential for heavy-ion scattering, and the resulting potentials were shown to reproduce the observed elastic scattering for a large number of systems with bombarding energies from 5 to 20 MeV per nucleon.
1,078 citations
TL;DR: In this article, Bruggeman and Maxwell Garnett showed that the dielectric properties of microscopically rough layers of thicknesses 100-500 \AA{}A are accurately modeled in the effective medium approximation.
Abstract: Using measured dielectric function data from 2.1 to 5.5 eV for chemical-vapor-deposition---grown smooth amorphous ($a$-Si) and microscopically rough fine-grained polycrystalline ($p$-Si) films, we show that the dielectric properties of microscopically rough layers of thicknesses 100-500 \AA{}A are accurately modeled in the effective-medium approximation. These microscopically rough layers show essentially no macroscopic light scattering, and thus are inaccessible to measurement by usual scattering techniques. The unambiguous identification of microscopic roughness, as opposed to, e.g., an overlying oxide, is shown to require a spectroscopic capability. Statistical-analysis techniques are introduced to determine model parameters systematically and objectively, and also to establish correlations and confidence limits that show which parameters are defined by the data and which are statistically indeterminate. A best-fit five-parameter model for the sample with the thickest surface region shows that the density profile is characteristic of hemispherical, not pyramidal, irregularities. This indicates that surface roughness arises from a three-dimensional nucleation and growth process in these samples. In a comparison of the three one-parameter effective-medium models, Bruggeman and Maxwell Garnett(2) theories are found to adequately represent the data, while the Lorentz-Lorenz model, previously used exclusively to model roughness in single-wavelength applications, predicts only qualitatively the spectral dependence and gives poor results.
937 citations
897 citations
TL;DR: In this article, the authors studied the thermal conductivity of non-metallic crystals at temperatures comparable to or higher than the Debye temperature, where the dominant carriers of thermal energy are phonons and the dominant scattering mechanism is the intrinsic phonon-phonon scattering.
Abstract: Publisher Summary This chapter reviews the thermal conductivity of nonmetallic crystals at temperatures comparable to or higher than the Debye temperature. It deals with the intrinsic behavior of such pure crystals at high temperatures. In such crystals, the dominant carriers of thermal energy are phonons and the dominant scattering mechanism to be considered is the intrinsic phonon–phonon scattering. This is a small section of the much larger problem of the thermal conductivity of nonmetallic solids and clearly it neglects possible heat transport by photons, charge carriers, polarons, and magnons. It also neglects other possible phonon scattering mechanisms such as isotopes, impurities, vacancies, charge carriers, dislocations, grain boundaries, and crystal boundaries. It presents the absolute value of the thermal conductivity, K, as determined by phonon–phonon scattering, the temperature dependence of K, the volume dependence of K, the change in K upon melting, and the minimum value of K. The chapter discusses a composite curve for the thermal conductivity versus temperature of pure KCl measured at a constant pressure of, say, one atmosphere.
734 citations
TL;DR: In this article, the relativistic Hartree-Fock atomic form factor F (x,Z) is computed for all elements Z = 1 to 100, for photon energies 100 eV to 100 MeV (λ=0.000 124 A=12.4 nm).
Abstract: Tabulations are presented of relativistic Hartree‐Fock atomic form factors F (x,Z), for values of x (=sin(ϑ/2)/λ from 0.01 to 109 A−1, for all elements Z=1 to 100. For Z=1, F (x,Z) is given by the exact expression of Pirenne. For Z=2 to 98, x=0.01 to 2.0 A−1, the tabulated values are those of Cromer and Waber given in the International Tables for X−Ray Crystallography (Vol. IV, 1974), based in part on the work of Doyle and Turner. For Z=21 to 92, x=2.2 to 6.0 A−1, the present tables are based on the values of Doyle and Turner and additional values (Z=44,60,68, and 74) as given by O/verbo/. For Z=3 to 20.x=2.2 to 45 A−1, Z=21 to 92,x=62 to 45 A−1 the tables are interpolated from values given for 36 elements by O/verbo/, extended to x=109 A−1 using O/verbo/’s corrections to the Bethe‐Levinger K‐shell expression. The remainder of the table is filled in by interpolation and extrapolation, guided for high x‐values by the Bethe‐Levinger result. Tables of relativistic coherent (Rayleigh) scattering cross sections, obtained by numerical integration of the Thomson formula weighted by F2(x,Z), are presented for all elements Z=1 to 100, for photon energies 100 eV (λ=124 A=12.4 nm) to 100 MeV (λ=0.000 124 A=12.4 fm). Departures from the nonrelativistic coherent scattering cross sections tabulated in J. Phys. Chem. Ref. Data 4, 471 (1975) are less than 1% for Z<20. However for a high‐Z element such as lead, for example, the relativistic coherent scattering cross section is systematically higher by less than 0.4% below 1 keV, by 8% at 100 keV and by 13% above 1 MeV.
503 citations
TL;DR: In this article, general electromechanical reciprocity relations are applied to the calculation of elastic wave scattering coefficients observed at the electrical terminals of the transducer used in performing an experiment.
369 citations
TL;DR: In this article, the shape of the distance distribution function enables one to distinguish and recognize directly and rationally the following types of particles: compact globular particles; particles elongated in one dimension, with constant and with variable cross-section; spherical vesicles.
Abstract: The distance distribution function contains all the accessible information about the scattering medium. It is possible to determine the following particle parameters from this function: maximum dimension of the particle, radius of gyration, and zero-angle intensity (molecular weight). The shape of the distance distribution function enables one to distinguish and to recognize directly and rationally the following types of particles: compact globular particles; particles elongated in one dimension, with constant and with variable cross-section; spherical vesicles. The thickness of flat particles as well as the inner and outer diameter of spherical vesicles can be determined from the distance distribution function. Inhomogeneous particles with at least two regions of electron densities differing in their signs show typical features in the distance distribution. These characteristics can be found without further assumptions, independently of the shape of the particle. For concentric shells with different electron densities it is possible to obtain some general information about their structure. Residual concentration effects cannot be overlooked in real space. The formation of dimers can be analyzed with the aid of the distance distribution function.
341 citations
01 Jan 1979
325 citations
TL;DR: In this paper, the authors derived thresholds and linear growth rates for stimulated Brillouin and Raman scattering and for the parametric decay instability by using arguments of energy transfer.
Abstract: Thresholds and linear growth rates for stimulated Brillouin and Raman scattering and for the parametric decay instability are derived by using arguments of energy transfer. For this purpose an expression for the ponderomotive force is derived. Conditions under which the partial pressure force due to differential dissipation exceeds the ponderomotive force are also discussed. Stimulated Brillouin and Raman scattering are weakly excited by existing incoherent backscatter radars. The parametric decay instability is strongly excited in ionospheric heating experiments. Saturation theories of the parametric decay instability are therefore described. After a brief discussion of the purely growing instability the effect of using several pumps is discussed as well as the effects of inhomogeneity. Turning to detailed theories of ionospheric heating, artificial spread F is discussed in terms of a purely growing instability where the nonlinearity is due to dissipation. Field-aligned short-scale striations are explained in terms of dissipation of the parametrically excited Langmuir waves (plasma oscillations); they might be further amplified by an explosive instability (except at the magnetic equator). Broadband absorption is probably due to scattering of the electromagnetic pump wave into Langmuir waves. This absorption is probably responsible for the ‘Overshoot’ effect: the initially observed level of parametrically excited Langmuir waves is much higher than the steady state level.
TL;DR: In this article, a shot model of surface roughness is introduced to gain further insight into the relationship between scattering and surface features, in particular the correspondence between "1/02" scattering and electronic noise.
Abstract: In the smooth-surface limit, the angular distribution of the light scattered from a surface maps the power spectral density of its residual surface roughness. This result is essentially independent of the scattering theory used and the statistical properties of the surface roughness. The power spectral densities of engineering surfaces are generally broad and increase with increasing spatial wavelength. As a result, practical surface finish parameters are not intrinsic properties of the surface, but depend, with varying degrees of sensitivity, on the bandwidth limits inherent in their measurement or dictated by their application. These issues are discussed with reference to two classes of finish parameters: those related to the central moments of the scattering spectrum, and those related to the coefficients in the expansion of the shape of the spectrum in inverse powers of the scattering angle. The significance of "1/02" scattering in this context is emphasized. A shot model of surface roughness is then introduced to gain further insight into the relationship between scattering and surface features. In this model inverse power terms are related to "edge" scattering effects from critical points in various types of elemental microdefects. The relationship between this view and electronic noise is pointed out; in particular, the correspondence between "1/02" scattering and "1/f" or flicker-noise phenomena.
TL;DR: In this article, a technique for single body-centred cubic (b.c.) colloidal crystals, well suited for light scattering and having particular orientations, was described, which reduces interference by multiple scattering and renders the particle scattering factor nearly constant through those scattering angles where the most useful information concerning crystal structure and dynamics appears.
Abstract: Colloidal suspensions of highly charged, monodisperse polymer spheres exhibit long-range (crystalline) translational ordering in appropriate conditions of charge, number density, counterion concentration and temperature1–5. These ‘colloidal crystals’, which can conveniently be made to have lattice parameters comparable to or greater than optical wavelengths, offer unique opportunities for the study of the collective static and dynamic behaviour of strongly interacting spherical particles. For example, such systems may readily be probed by relatively simple but powerful light scattering spectroscopic techniques6,7. Furthermore, the ordering itself offers intrinsic advantages, both experimental (for example, fluctuations normally observable only about the k-space origin appear about Bragg spots, with reduced stray light and multiple scattering effects), and theoretical (the simplicity of calculating on the basis of a known rather than only statistically defined structure is well appreciated from experience with atomic solids and liquids). To exploit these ordered structures fully, reliable methods of producing orientated single crystals suitable for light scattering and other optical studies must be developed. For light scattering from bulk samples the primary requirement is that the ratio of interparticle spacing to diameter, a/d, be sufficiently large. This reduces interference by multiple scattering and renders the particle scattering factor nearly constant through those scattering angles [|k|<(2→5)2π/a] where the most useful information concerning crystal structure and dynamics appears. We now describe a technique whereby single body-centred cubic (b.c.c.) colloidal crystals, well suited for light scattering and having particular orientations, may be produced.
TL;DR: In this paper, a relation from vector scattering theory has been used to predict the angular distribution of scattered light from optical surfaces as a function of the wavelength, optical constants of the material, and spectral density function.
Abstract: A relation from vector scattering theory has been used to predict the angular distribution of scattered light from optical surfaces as a function of the wavelength, optical constants of the material, and spectral density function. For calculations of one-dimensional (two-dimensional) scattering, the spectral density function of the surface roughness is obtained from the Fourier transform (Hankel transform) of the autocovariance function, which in turn is determined from surface-profile data. Measured statistics presented for various types of optical surfaces indicate that there are three basic components of surface structure: long-range waviness, short-range random roughness, and periodicity; one or more of which may be present on a given surface. Averaged and unaveraged surface-profile data for the same surface are shown to be consistent. Experimental data are presented that yield an exponential autocovariance function, and give a reasonably good fit to a Poisson distribution of zero crossings. Finally, angular scattering values calculated using measured surface statistics with vector scattering theory are compared to scattering values measured on the same surface. The shapes of the measured and calculated curves are similar, but the magnitudes are not. However, the rms surface roughnesses calculated from total integrated scattering measurements are in excellent agreement with values measured directly on these same surfaces.
TL;DR: A three-dimensional diffuse reflectance equation for a two-layer tissue model was developed using photon diffusion theory to investigate the effects of various tissue and system parameters on the partial reflectance from the second tissue layer.
Abstract: A three-dimensional diffuse reflectance equation for a two-layer tissue model was developed using photon diffusion theory. In this model, tissue was considered to consist of two homogeneous isotropically scattering layers whose scattering and absorption constants were expressed as a linear sum of those of whole blood and a blood-free tissue component; tissue hemoglobin content and oxygen saturation were then expressed in terms of these total tissue parameters. Reflectance predictions given by the two-layer equation were used to investigate the effects of various tissue and system parameters on the partial reflectance from the second tissue layer; among such parameters significantly affecting deep-layer reflectance are the tissues scattering constants, its geometry, and the geometry of the optical transducer. When the penetration depth of the incident photons is small compared with the thickness of the first layer, reflectance contributions from the second layer are negligible, and a single-layer approximation would be adequate; resultant reflectance errors range from 6 to 8 percent of the total reflectance, for source-detector separations in the range from 1 to 4 mm. However, when the photon penetration depth is large with respect to first-layer thickness, the effects of deep layers are both important and strongly dependent on transducer geometry; partial reflectances range to 50 percent of the total when the source-detector separation is 4 mm.
TL;DR: In this paper, the authors survey both experimental and theoretical research on electronic surface resonances as observed by scattering of low-energy (<1 keV) electrons and present plots of the electronic surface resonance band structure E (k/sub parallel/) (E=resonance energy, k/subpar/ =reduced surface-parallel momentum).
Abstract: Electrons incident on a crystal surface can be temporarily trapped in surface states at energies above the vacuum level. These temporary or nonstationary surface states are observed as narrow fluctuations of elastic scattering intensity with respect to variation of electron energy and incidence direction. The scattering process is called electronic surface resonance scattering. The temporary surface states that are intermediate states in resonance scattering are called electronic surface resonances. The article surveys both experimental and theoretical research on electronic surface resonances as observed by scattering of low-energy (<1 keV) electrons. A critical account of experiments on Al(001), W(001), Ni(001), and oxygenated Ni(001) surfaces is offered together with theoretical commentary. Plots of the electronic surface resonance band structure E (k/sub parallel/) (E=resonance energy, k/sub parallel/ =reduced surface-parallel momentum) are compiled and the signficance of E (k/sub parallel/) plots for surface characterization is indicated.
TL;DR: In this paper, the scattering rates for the electron impurity and the electron-phonon interactions in semiconductor multilayer heterojunction structures were calculated, and it was found that phonon scattering is enhanced in such structures, whereas, impurity scattering can be strongly reduced at low temperatures as found experimentally.
Abstract: The scattering rates for the electron‐impurity and the electron‐phonon interactions in semiconductor multilayer heterojunction structures are calculated. It is found that phonon scattering is enhanced in such structures, whereas, impurity scattering can be strongly reduced at low temperatures as found experimentally.
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01 Aug 1979
TL;DR: In this paper, Stieltjes-Tchebycheff moment-theoretic approach to molecular photoionization is used to calculate the resonance width of molecules.
Abstract: Application of the Close-Coupling Method to Electron-Molecule Scattering.- The Coupled-Channels Integral-Equations Method in the Theory of Low-Energy Electron-Molecule Scattering.- Roundtable on Numerical Methods.- Contribution of the Variable Phase Method to the Frame Transformation Theory of Rotational Excitation of Molecules by Electron Impact.- The R-Matrix Method for Electron-Molecule Scattering: Theory and Computation.- The T-Matrix Method in Electron-Molecule Scattering.- Roundtable on L2-Methods.- The Separable Approximation in Multichannel Electron-Molecule Collisions.- Nonempirical Polarization in Low-Energy Electron-Molecule Scattering Theory.- R-Matrix Calculations for Electron Scattering by Diatomic Molecules.- Discussion on Electron-Molecule Scattering.- Polarization Potentials for Electron Scattering.- Vibrational Excitations of Low-Energy e-CO Scattering.- Improved Hybrid Theory Calculation of e-N2 Vibrational Excitation.- Stieltjes-Tchebycheff Moment-Theory Approach to Molecular Photoionization Studies.- The Continuum Multiple-Scattering Approach to Electron-Molecule Scattering and Molecular Photo ionization.- Molecular Resonance Phenomena.- Stieltjes-Moment-Theory Technique for Calculating Resonance Widths.- Progress Toward the Application of Complex Coordinte and Complex Basis Function Techniques to Molecular Resonance Calculations.- Discussion on Photoionization and Molecular Resonances.- A Modification of the Langhoff Imaging Technique.- Workshop on L2-Methods.- Workshop on Single-Center Techniques.
TL;DR: In this article, the transition from superconductivity to ferromagnetism was studied and a first-order transition to uniform ferromagnetic magnetism was predicted, but preceded by magnetic critical scattering which peaks at a finite wave vector.
Abstract: Electromagnetic effects are shown to govern the transition from superconductivity to ferromagnetism. A first-order transition to uniform ferromagnetism is predicted generally, but preceded by magnetic critical scattering which peaks at a finite wave vector.
TL;DR: In this paper, a scalar theory for scattering from multilayer coatings due to surface roughness is presented, which assumes that the roughness of the top surface of a given layer is due to the previously deposited layers and to the variations in thickness of the layer itself.
Abstract: A scalar theory for scattering from multilayer coatings due to surface roughness is presented. A new model is considered which assumes that the roughness of the top surface of a given layer is due to the roughness introduced by the previously deposited layers and to the variations in thickness of the layer itself. The variations in the layer thickness are assumed to be uncorrelated from one layer to the next, but the roughnesses of the various surfaces are partially correlated. This model is compared to two existing models: one which assumes that the surfaces of the layers are completely uncorrelated and another which assumes that all of the surfaces are identical to that of the substrate. A fourth model is also introduced which assumes that the scattering is due to variations of refractive index within each layer. A matrix formulation for calculating the total integrated scattering and the change in specular reflectance and transmittance is presented. Predictions of the four different models are compared for several multilayer designs.
01 Jan 1979
TL;DR: In this article, the effect of long-range fluctuation in impurity potential on the Electron Light Scattering in Heavily Doped Semiconductors is discussed.
Abstract: Section I Hydrodynamic Instabilities and Critical Phenomena.- To Scale or not to Scale? - The Puzzle at the Lambda Point of Liquid 4He.- Transition to Turbulence in Couette-Taylor Flow.- Hydrodynamic Instabilities and Turbulence.- Light Scattering from Gels and a Single Polymer Chain near Phase Transitions.- Interferometric Studies of Thick Film Critical Behavior.- Section II Physics in Two Dimensions and Defects.- Melting and Liquid Crystals in Two Dimensions.- Light Scattering Studies of Molecular Orientation Fluctuations in Two Dimensions.- Multiphonon Boundary of the Excitation Spectrum.- Raman Scattering Spectra of Proustite and Pyrargyrite Crystals in Low Temperature Phases.- Finite Field Local Field Catastrophe - Application to the Spectra of KCNxCl1?x.- The Effect of Long Range Fluctuations in Impurity Potential on the Electron Light Scattering in Heavily Doped Semiconductors.- Resonant Scattering and Trapping of 29 cm?1 Acoustic Phonons in Ruby Crystals.- Section III Non-Local and Transient Phenomena.- Some Aspects of the Theory of Surface Polaritons.- Recent Developments in Non-Local Optics.- Resonant Brillouin Scattering of Exciton Polaritons.- Ultraslow Optical Dephasing of Pr3+:LaF3.- Picosecond Raman Gain Studies of Molecular Vibrations on a Surface.- Section IV Spins and Excitons.- Brillouin-Mandelstam Scattering of Light in Antiferromagnetic CoCO3.- Observation of Pure Spin Diffusion Without Charge Transport by Spin Flip Raman Scattering.- Spin-Flip Scattering from Photoexcited Excitons in SiC.- The Scattering of Light by Spin Waves on Ferromagnetic Surfaces.- Relaxation of Energy and Polarization in the Resonant Secondary Emission Spectra of Semiconductors.- Resonant Raman Scattering from Stress-Split Forbidden Excitons in CU2O.- Low Frequency Exciton and Raman Scattering Spectra of CoCO3.- Theoretical and Experimental Determinations of Raman Scattering Cross Sections in Simple Solids.- Section V Resonance Scattering and Charge Excitations.- Resonant Secondary Emission by Impurities in Crystals.- The Raman Scattering and Hot Luminescence of Self-Trapping Excitons.- Phenomenological Description of Light Scattering and Thermal Radiation.- Raman Scattering from Plasmon-Phonon Coupled Modes in GaP.- Interaction Between Localized Carriers in the Accumulation Layer and Extended Bulk LO Phonons in InSb and GaSb: Raman Interference Lineshapes.- Inelastic Light Scattering by the Two Dimensional Electrons in Semiconductor Heterojunction Superlattices.- On the Distinction Between Resonant Scattering and Hot Luminescence: Application of Theory to Experiment.- Section VI Phase Transitions.- Light Scattering Near Structural Phase Transition Points in Pure Crystals and in Crystals Containing Defects.- Raman Scattering From Charge Density Waves and Superconducting Gap Excitations in 2H-TaSe2 and 2H-NbSe2.- Quasielastic Light Scattering Near Structural Phase Transitions.- High Resolution X-Ray and Light Scattering Spectroscopy of Liquid Crystals.- Optics and Electrooptics of Chiral Smectics.- The Size, Shape and Polydisperity of Micelles of Amphiphillic Molecules.- Resonance Raman Studies of Visual Pigments.- A Nanosecond Probe of Hemoglobin Dynamics Using Time Resolved Resonance Raman Scattering.- Section VII Multi-Photon Spectroscopy.- Recent Results in Four-Photon Spectroscopy of Condensed Media.- Recent Progress in Four-Wave Mixing Spectroscopy in Crystals.- Coherent Raman Ellipsometry of Liquid Water: New Data on the Vibrational Stretching Region.- Time Resolved Coherent Anti-Stokes Raman Scattering in Weakly Disordered Molecular Crystals.- Intense Light Resonance Scattering: Spectra and Photon Correlations.- Section VIII Resonance Scattering and Surface Enhanced Raman Scattering.- Intensity Effects in Resonance Light Scattering.- The Spontaneous Diffraction of Light by Resonance Atoms.- Giant Raman Scattering by Molecules Adsorbed on Metals: an Overview.- Raman Spectroscopy of Molecular Monolayers in Inelastic Electron Tunneling Spectroscopy Junctions.- A Theory of "Giant Raman Scattering" by Adsorbed Molecules on Metal Surfaces.- Concluding Remarks.- Participants.- Author Index.
TL;DR: In this article, a set of total cross sections for scattering of electrons by Ne, Ar, Kr and Xe has been evaluated over the energy range of about 20 to 3000 eV by means of the analysis of experiments and theories.
Abstract: A set of total cross sections for scattering of electrons by Ne, Ar, Kr and Xe has been evaluated over the energy range of about 20 to 3000 eV by means of the analysis of experiments and theories on total cross sections for elastic scattering, ionisation and excitation, and on differential cross sections for elastic and inelastic scattering. The total cross sections for scattering of electrons are evaluated by adding those for ionisation, excitation and elastic scattering and they are accurate to about 5-10%. They appear to be in very good agreement with the recent experimental results on total electron scattering of Wagenaar et al. (1978).
TL;DR: In this paper, the vibrational spectrum of hydrogen adsorbed at ⪆90 K on Pt(111) has been studied by electron energy loss spectroscopy, and it has been shown that impact scattering gives an important contribution to the vibration cross section.
TL;DR: In this paper, the secondary-electron spectra were excited by Al-$K\ensuremath{\alpha}$ (1487 eV) photons and were measured from evaporated dielectric films with an electrostatic hemispherical analyzer of about 0.03-eV resolution.
Abstract: Secondary-electron energy distribution curves (EDC's) and the total secondary-electron yields relative to such for gold have been measured for seven semiconductors for which electron-electron scattering losses within the emitter were considered dominant and for nine insulators (alkali halides) for which electron-phonon scattering losses were expected to be dominant in the transport process. The secondary-electron spectra were excited by Al-$K\ensuremath{\alpha}$ (1487 eV) photons and were measured from evaporated dielectric films (of about 0.3 \ensuremath{\mu} thickness) on conducting substrates with an electrostatic hemispherical analyzer of about 0.03-eV resolution. Some of the dielectric photoemitters have appreciably narrower energy distributions and higher yields than has gold; CuI and CsI have EDC widths at half-maximum of about one-third of that for gold, and yield values of 11 and 30 times greater. The FWHM and secondary-electron yield for gold were measured to be about 4 eV and 0.50 electrons per normally incident photon, respectively. The shapes of the EDC's were found to be essentially unchanged for photon excitation in the 0.1-10-keV region. Strong structural features appear only in the alkali halide EDC's, and it is proposed that these are mainly the result of single-electron promotion of secondaries from the valence band by plasmon deexcitation. A relatively simple model for x-ray photoemission has been developed which assumes that direct excitation of secondaries by photoelectron and Auger-electron "primaries" is the dominant excitation mechanism, and accounts for both electron-electron and electron-phonon scattering in the transport process. Free-electron conduction-band descriptions are assumed. The theoretical and experimental curves are in satisfactory agreement.
TL;DR: It is shown that, for oblique incidence, the scattering properties of a long slender prolate spheroid resemble those of an infinitely long circular cylinder.
Abstract: In the present paper, the light scattering characteristics of spheroidal particles are evaluated within the framework of a scattering theory developed for a homogeneous isotropic spheroid. This approach is shown to be well suited for computing the scattering quantities of spheroidal particles of fairly large sizes (up to a size parameter of 30). The effects of particle size, shape, index of refraction, and orientation on the scattering efficiency factors and the scattering intensity functions are studied and interpreted physically. It is shown that, in the case of oblique incidence, the scattering properties of a long slender prolate spheroid resemble those of an infinitely long circular cylinder.
TL;DR: In this paper, a new equation for the light scattering (or small angle x-ray or neutron scattering) of a concentrated p-component mixture of spherical (colloidal) particles in a low molecular weight solvent was derived.
Abstract: In a previous paper (I), a new equation for the light scattering (or small angle x‐ray or neutron scattering) of a concentrated p‐component mixture of spherical (colloidal) particles in a low‐molecular weight solvent was derived. Use was made of Baxter’s factorization of the direct correlation matrix. It was found that the light scattering intensity can be formulated in factorized form as well. The formalism was applied to a multicomponent system of hard spheres treated in the Percus–Yevick approximation. For zero scattering angle, a rather simple, exact expression was obtained. In this paper it is proved that a closed expression can also be obtained for finite scattering angles. It contains at most 18 (averaged) functions of the scattering angle for any number of hard sphere components. This makes it possible to apply the equation to a continuous distribution of hard sphere diameters. A series expansion is given for small scattering wave numbers.
TL;DR: In this article, the relativistic treatment of photons by electrons in a strong magnetic field is performed for electrons in the lowest Landau level by specializing to the nonrelativistic region.
Abstract: The differential cross section for scattering of photons by electrons in a strong magnetic field is calculated The relativistic treatment is performed for electrons in the lowest Landau level By specializing to the nonrelativistic region, cross sections for Thomson scattering are given for an arbitrary direction of the photon with respect to the magnetic field These results are in agreement with previous calculations The relativistic cross sections are numerically calculated to compare them explicitly with the nonrelativistic case and to present numerical values which can be used, for instance, in practical applications to neutron stars
TL;DR: A review of theoretical approaches to the problem of diffractive scattering at high energies is presented in this article, where a phenomenological analysis of experimental data on inelastic diffractive processes is carried out and the main properties of diffraction are discussed.