Theory Of Light Scattering Research Articles

Monte Carlo Simulation of Optical Properties of Wake Bubbles

Based on Mie scattering theory and the theory of multiple lightscattering, the light scattering properties of air bubbles in a wakeare analysed by Monte Carlo simulation. The results show thatbackscattering is enhanced obviously due to the existence of bubbles,especially with the increase of bubble density, and that it is feasibleto use the Monte Carlo method to study the properties of lightscattering by air bubbles.

On the theory of light scattering in gases

The history of development of the theory of lightscattering and dispersion in gases is outlined, from the worksof Rayleigh, Planck, and Mandelstam to those of Lorentz andEinstein. It is shown that of central concern in these studieswas actually the problem of thermal fluctuations in a medium.A formula for the permittivity ε(ω) taking account of radiation friction forces is derived for the case of an isotropicmedium.

T-matrix Theory of Light Scattering by Uniformly Anisotropic Spherical Scatterers

We extend the T -matrix approach to light scattering by spherical particles to the simple case in which the scatterers are optically anisotropic. Specifically, we consider the spherical particles that are uniformly anisotropic. We find that the T -matrix theory can be formulated using a modified T -matrix ansatz with suitably defined modes. We derive these modes by relating the wave packet representation and expansions of electromagnetic field over spherical harmonics. We present preliminary results of numerical calculations of the scattering by spherical droplets. We concentrate on cases in which the scattering is due only to the local optical anisotropy within the scatterer.

6. Mie-Seminar “Theory of Lightscattering and its Application”

6. Mie-Seminar “Theory of Lightscattering and its Application”

6. Mie‐Seminar “Theory of Lightscattering and its Application”

6. Mie‐Seminar “Theory of Lightscattering and its Application”

Isotopic light scattering of lipid vesicles. Water permeation and effect of α-tocopherol

The influence of the index of refraction of the solvent on light scattering properties of lecithin bilayer vesicles is described. Large vesicles (diameter 300 nm) are considered where one lamella separates the intravesicular compartment from the external medium. Stationary and transient cases are distinguished with special emphasis on the isotopic substitution of the solvent, i.e. H 2O vs. D 2O. Theoretical calculations based on the Mie theory of light-scattering are in accord with results from experiments. The two stationary cases considered serve to calibrate the numerical calculations and illustrate the capability of the method. Transient experiments allow the determination of permeation rates; in particular the D 2O/H 2O permeability coefficients can be obtained. Single component vesicular lecithin bilayers and ones containing tocopherol are compared. In the crystalline state the incorporation of tocopherol increases the fluidity of the lipid bilayer in parallel with the water permeation rate.

Corrections: Theory of Light Scattering and Propagation in Dilute Polymer Solutions: Wormlike Chain Model with Intrinsic and Shape Optical Anisotropies.

Corrections: Theory of Light Scattering and Propagation in Dilute Polymer Solutions: Wormlike Chain Model with Intrinsic and Shape Optical Anisotropies.

THEORY OF BRILLOUIN SCATTERING BY AN ISOTROPIC ELASTIC PLATE

The theory of surface-ripple light-scattering by the bending (undulation) and longitudinal (peristaltic) modes of an elastic plate is presented, together with results of illustrative numerical calculations.

Theory of Light Scattering by Amorphous Absorbing Media

The present paper studies the determination of structural statistics of amorphous absorbing media from the distribution of intensity of scattered light. Assuming a gaussian distributed inhomogeneity, the form of the correlation function for absorbing materials is discussed. Furthermore, the relationship between the correlation function and the scattered intensity is established in both the Fresnel and Fraunhofer regions. The first Born approximation is discussed, as well as the difficulties in solving the inverse statistical problem due to the complex nature of the permittivity.

Theory of Light Scattering by an Isotropic System Composed of Anisotropic Units. Out-of-Plane Scattering

A previous theory [Polym. J., 3, 67 (1972)] of light scattering by an isotropic system composed of anisotropic units is extended to the case of the out-of-plane scattering where the intensity of scattered light is measured outside the scattering-plane. Two cases are considered: the intensity is measured photoelectrically in one and photographically in the other. It is shown that the out-of-plane scattering at any direction can be reduced to the in-plane scattering with the planes of polarization of the polarizer and the analyzer inclined properly (by ψ and ω) to the vertical direction. In the photoelectric case the intensity I(ψ,ω) of the latter scattering can be expressed as I(ψ,ω)=a IVv+b IHv+c IHh+d I(45°, 45°), where IHv≡I(0°, 90°) etc. I(45°, 45°) (or some alternative) is found to give information substantially independent of those which were previously studied on IVv, IHh, and IHh. A refined method for analysis of experimental data is proposed on the basis of the four intensity functions described above. In the photographic case three photographs are shown to give all of the information, which are taken with such experimental arrangements that the plane of polarization of the polarizer is set vertical while that of the analyser is set vertical, (Vv pattern) or horizontal (Hv pattern).

Theory of Light Scattering by an Isotropic System Composed of Anisotropic Units with Application to the Porod–Kratky Chain

Theory of Light Scattering by an Isotropic System Composed of Anisotropic Units with Application to the Porod–Kratky Chain

Theory of Light Scattering From Shear Waves in Liquids

Recent high-resolution experiments have shown that the depolarized-light scattering spectra of a few liquids contain, besides the usual broad background, a sharp component. This component is split into two symmetric peaks. It has been explained as arising from a coupling between thermally excited shear waves and molecular orientations. The theories of Leontovich and Rytov on this coupling are critically revised, and a new theory is proposed which seems to give a better agreement with the experimental results.

Hole Theory of Light Scattering by Liquids*

A slightly modified form of Frenkel’s hole theory of liquids is developed and it is shown that three characteristic hole parameters can be chosen in such a fashion that quantitative agreement between theory and experiment is obtained for numerous thermal and mechanical properties of liquid benzene. The Cummins–Gammon formulas for Rayleigh and Brillouin scattering of liquids are deduced from the hole theory and, thus, it is demonstrated that the hole theory provides a suitable model for the nonpropagating density fluctuations of the phenomenological scattering theory.

Theory of Light Scattering in Amorphous Media

(1968). Theory of Light Scattering in Amorphous Media. Optica Acta: International Journal of Optics: Vol. 15, No. 5, pp. 451-486.

Theory of Light Scattering by Magnetic Crystals

A theory of the Raman scattering of light due to spin systems in magnetic crystals is developed by using the spin dependent electric polarizability. The polarization characteristics of the scattering, the scattering intensity and its temperature dependence are treated with particular referenc to antiferromagnetic iron group fluorides, where one- and two-magnon scatterings have been observed. Agreement between the theory and the experimental results is satisfactory.

Theory of Light Scattering in Doubly Relaxing Liquids

The theory developed by R. D. Mountain [J. Res. Natl. Bur. Std. U. S. 70A, 207 (1966)] to describe the scattering of monochromatic light from density fluctuations in a liquid where a singly relaxing internal degree of freedom is weakly coupled to the translational modes has been extended to the case of a liquid exhibiting double relaxation effects. The predicted spectral distribution of the scattered light and velocity dispersion are presented. The applicability of the results in current experimental studies of benzene and other liquids is considered. [Research supported in part by the Office of Naval Research.]

Green's Function Method in the Theory of Light Scattering by Impurity Centres in Solids

AbstractThe spectra of resonant, Raleigh, and Raman scattering of light by impurity centres are calculated by the method of Green's functions and operator arrangement along the integration contour, taking account of anharmonicity. A general expression is obtained for the scattering spectrum. The dependence of the phonon and non‐phonon parts of the spectrum on temperature and the nature of the host crystal are discussed in detail. As the frequency of the exciting light approaches the impurity absorption region, the integral scattering intensity increases with the absorption coefficient of the impurity centres.

Theory of Light Scattering by Thin Rodlike Macromolecules in a Liquid Subjected to Shear

The light scattering by thin rodlike particles in a liquid subjected to shear is calculated on the basis of the Rayleigh-Gans treatment. The calculations are made for both unidirectional laminary flow and for flow of periodically alternating direction. The calculation is carried out by two methods: the interference factor P is expressed in terms of a power series of G/D, where G and D are the rate of shear and the rotatory diffusion constant, respectively, of the rod rotating around its minor axis. This treatment is applicable to sufficiently low G/D values. The result for a very wide range of rate of shear is obtained by using the Peterlin distribution function of particle axis. Numerical calculation shows that both results agree in a region of G/D below about two if the axial ratio is large enough. The theoretical results appear to agree with the experimental ones.

The Theory of Light Scattering and X-ray Low Angle Scattering by Semi-stiff Chain Molecules

Numerical values of the normalized intensity of scattering by semi-stuff chain molecules are calculated. The method depends on the calculation of the inverse Laplace transform of an expression first obtained by Daniels, which is also derived in this paper by an alternative method. The values obtained from this calculation are compared with those given by Peterlin's formula. The normalized intensity is also calculated for a polydisperse system of chains of constant stiffness parameter.

Light-scattering by dislocation networks in single crystals of potassium chloride

The theory of light-scattering by systems of linelike scattering units is presented in a form suitable for studying light-scattering by dislocation networks in transparent solids. The theory is applied to light scattering by single crystals of Harshaw potassium chloride which was measured for different wave-lengths and scattering angles and for different orientations of the crystal with respect to the direction of the incident light beam. It was found that the scattering system has fourfold axes of rotation parallel to the 〈100〉 directions of the crystal, and a partial Fourier analysis of the scattering power indicates that the scattering is mainly produced by networks of dislocations in the {100} planes, the individual lines being mostly directed along the 〈100〉 directions of the crystal. The rods have a width of about 1000 A and are, most probably, not perfectly straight; the latter feature prevents an estimate of their length.