Light scattering by aggregates

Kimura H, Kolokolova L, Mann I Optical properties of cometary dust constraints firom numerical studies on light scattering by aggregate particles, Astron Astrophys 407(1) L5-L8, 2003. 

Parkash, J., J.H. Robblee, J. Agnew, E. Gibbs, P. Collings, R.F. Pasternack, and J.C de Paula. 1998. Depolarized resonance light scattering by porphyrin and chlorophyll a aggregates. Biophys. J. 74 2089-2099. 

Often the UV absorption tails into the visible due to light scattering by the microparticles, although the Amax is usually very close to that in solution. The aggregate CD spectrum, however, is markedly different from the solution-state spectrum, showing an intense bisigned Cotton effect coincident with the UV due the Davidov coupling. 

Bottiger, J. R., E. S. Fry, and R. C. Thompson, 1980. Phase matrix measurements for electromagnetic scattering by sphere aggregates, in Light Scattering by Irregularly Shaped Particles, D. Schuerman (Ed.), Plenum, New York, pp. 283-290. 

However, the most intuitive way of measuring aggregate formation in solution is the measurement of the light scattered by protein-tannin particles. In fact nephelometry and other light-scattering measurement techniques have been widely used to study protein-tannin interactions [33, 34, 44—49]. 

Wang, G.M., and Sorensen, C.M., Experimental test of the Rayleigh-Debye-Gans theory for light scattering by fractal aggregates, Appl. Opt, submitted. 

Cellulose microcrystals can be suspended in dilute solution. Turbidity measurements suggest that the particles are not highly associated in the absence of added salt. In the presence of a low salt concentration, large aggregates are formed, as was shown by a study of light scattering by suspensions of ramie microcrystals 15). When the salt concentration is further increased, the microcrystals precipitate. Since the microcrystals... 

Figure 11. The intensity and polarization of light scattered by clusters with different structure of the surface layer. Additional CPs are placed in a random way on the outside of the completely regular compact cluster 1. The model for the random cluster 4 is also shown for comparison. The number of CPs is shown for each model. A picture of the aggregate after 30 CPs have been added to the surface also is shown.

Sorensen, C. M. (2001). Light scattering by fractal aggregates a review. Aerosol ScL Technol., 35, 648-687. 

Figure 9.4 Schematic representation of the scattered light intensity I(q) versus q =AnX sin 0/2, where 0 is the scattering angle, from an ensemble of fractal aggregates of dimension Df on a log-log plot [43], Reprinted with permission bom Aerosol Science Technology, Light scattering by fractal aggregates , 35, 648-687, Copyright 2001. Mount Laurel, NJ.

---