Determination of Particle Structure from Light Scattering

Abstract

Light scattering is well known as a useful tool in the investigation of the structure of particles. One of the disadvantages is that, whereas the scattering often may be calculated for a given structure, it has not been possible to carry out a Fourier inversion of the scattered intensity function to determine an unknown structure. There are two major difficulties which are immediately recognizable. (1) The phase as well as the amplitude of the scattered radiation must be measured, and (2) the usual technique of Fourier inversion is not applicable because it requires knowledge of the scattered wavefunction for experimentally unattainable values of parameters. Both of these problems are discussed, and it is noted that they may be overcome in certain cases of interest. A method of phase determination suited to optical wavelengths is suggested for scattering by a single particle. Further, for ``soft'' scatterers, a method of inverting the scattering data is developed that does not suffer from the difficulty associated with the Fourier method. Thus, the inversion may be carried through and the desired structure of a scatterer may be obtained.