Light scattering

About: Light scattering is a research topic. Over the lifetime, 37721 publications have been published within this topic receiving 861581 citations.

Mixtures of hard spheres in the Percus–Yevick approximation. Light scattering at finite angles

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.

Light scattering measurements of the repetitive supersonic implosion of a sonoluminescing bubble.

Abstract: Light scattering is used to measure the dynamics of the repetitive collapse of a sonoluminescing bubble of gas trapped in water. It is found that the surface of the bubble is collapsing with a supersonic velocity at about the time of light emision which in turn precedes the minimum bubble radius by about 0.03% of the period of the acoustic drive. These observations suggest that the shedding of an imploding shock mediates between the bubble collapse and light emission

Light scattering in soap solutions

Abstract: Soap solutions exhibit even lower osmotic activity than would be predicted if one assumed that soap existed in solution as simple undissociated molecules. Soap solutions alço conduct the electric current far better than would be expected from the observed osmotic effects. Attempting to explain these anomalies, McBain,' in 1913, suggested that the fatty soap ions aggregated in solution. Such colloidal aggregations of ions, which were termed micelles, would explain the low osmotic activity and relatively high conductivity of soap solutions. Since 1913, investigators have shown considerable interest in the determination of the size and shape of the micelle. McBainP proposed two different rnicelle species, which he said could coexist in solution: one a small, spherical, hydrated, ionic micelle, and the other a large, larnellar, weakly conducting micelle. While agreeing with McBain that the behavior of soap solutions pointed to the existence of micelles, Hartleya took the view that only the small spherical micelle was feasièle. On the basis of geometrical considerations, Hartley4 calculated that the micelle of a 16 carbon soap consisted of approximately 50 cetyl chains. He and Runnicles5 carried out diffusion experiments with cetyl pyridinium chloride and calculated from their results that the micelle of this soap contained about 70 paraffin chains. Ultracentrifuge and diffusion measurements by Miller and Andersson' on Duponal (sodium salts of sulfated aliphatic alcohols of chain length C S to C,,) led to a molecular weight of 12,500 for the mixed micelle. Hakala' has made diff usion measurements on sodium dodecyl sulfate solutions. If a spherical model for the micelle is assumed, the introdgction of his results into the Stokes-Einstein equation gives a value of 23.6 A for the radius. A molecular weight of about 25,000 (87 paraffin chains per micelle) is obtained from this value of the radius if a density equal to that of dodecane is taken. Vetter' studied the sodium salt of sulfonated di (2-hexyl) succinate, known commercially as Aerosol MA, and from density, viscosity, and diffusion data calculated an aggregation number of 24 for the micelle. Gonick and McBain' obtained cryoscopic evidence of micelle formation in aqueous solutions of severa1 non-ionic detergents. Assuming ideal behavior, their data indicate that a micelle consists of no more than 7 detergent molecules.

Optimum Forward Light Scattering by Spherical and Spheroidal Dielectric Nanoparticles with High Refractive Index

Abstract: High-refractive index dielectric nanoparticles may exhibit strong directional forward light scattering at visible and near-infrared wavelengths due to interference of simultaneously excited electric and magnetic dipole resonances. For a spherical particle shape, the so-called first Kerker’s condition can be realized, at which the backward scattering practically vanishes for some combination of refractive index and particle size. However, realization of Kerker’s condition for spherical particles is only possible at the tail of the scattering resonances, when the particle scatters light weakly. Here we demonstrate that significantly higher forward scattering can be realized if spheroidal particles are considered instead. For each value of refractive index n exists an optimum shape of the particle, which produces minimum backscattering efficiency together with maximum forward scattering. This effect is achieved due to the overlapping of magnetic and electric dipole resonances of the spheroidal particle at th...

Introduction to Classical and Modern Optics

Abstract: Preface. 1. Reflection and Refraction. 2. Thin Lenses. 3. Thick Lenses and Combinations of Lenses. 4. Mirrors. 5. Aberrations. 6. Stops and Pupils. 7. Gradient-Index, Fiber, and Integrated Optics. 8. Lens Design. 9. Optical Systems. 10. Systems Evaluation. 11. Interference. 12. Thin Films. 13. Coherence. 14. Diffraction. 15. Diffraction Gratings. 16. Light Scattering. 17. Polarization of Light. 18. Optical Data Processing. 19. Holography. 20. Light Sources and Detectors. 21. Radiometry/Photometry. 22. Absorption. 23. Lasers. 24. Relativistic Optics. Answers to Odd-Numbered Problems. Index.