Single Particle Light Scattering Measurements Using the Electrodynamic Balance

Abstract

An electrodynamic balance built into a light scattering photometer was used to measure the light scattering characteristics of single liquid droplets and spherical and nonuniform solid particulates in the particle size range 1.0 < D _p < 12 μm. The real and imaginary components of the complex refractive index and the particle diameter have been determined for polystyrene latex spheres, liquid droplets, and dust particles generated by exposing soils to high heat fluxes. The optical properties and particle sizes for spheres are determined by comparing the measured light scattering profiles (intensity versus angle) with Mie theory. This is accomplished by suspending single spheres in a laser beam, recording the intensity of the scattered light as a function of angle, and interpreting the results by means of the squares of the differences between N data points and the corresponding Mie theory values.

*This work was initiated and partly performed at the University of New Mexico, Department of Chemical and Nuclear Engineering.

Notes

*This work was initiated and partly performed at the University of New Mexico, Department of Chemical and Nuclear Engineering.