Radiative scattering cross sections: comparison of experiment and theory

Area of Science:

• Optics and Photonics
• Materials Science
• Physical Chemistry

Background:

• Accurate characterization of particle properties is crucial in various scientific fields.
• Understanding light scattering by particles is essential for applications like atmospheric science and material analysis.
• Previous methods often faced challenges in precisely determining particle size distribution and concentration simultaneously.

Purpose of the Study:

• To develop a method for obtaining the scattering particle distribution function and concentration.
• To determine the scattering coefficient of the medium as a function of wavelength.
• To validate the method by comparing experimental and theoretical radiative scattering cross sections.

Main Methods:

• Experimental radiative scattering cross sections were measured using a spectrophotometer with monodispersed polystyrene latex particles in water.
• Theoretical cross sections were calculated and compared with experimental data over a 0.40-0.70 micrometer wavelength range.
• A discrete bimodal particle size distribution model was employed to account for particle coagulation and adjusted for consistency.

Main Results:

• The method successfully yielded the scattering particle distribution function and concentration.
• A constant difference between experimental and theoretical cross sections, proportional to measurement error, was identified and corrected.
• The wavelength-dependent scattering coefficient for the medium was accurately obtained.

Conclusions:

• The comparison of experimental and theoretical scattering cross sections provides a robust method for particle characterization.
• The developed technique effectively corrects for measurement errors in particle volume concentration.
• This approach enables precise determination of particle properties and optical coefficients for spherical particles.