Light Scattering (LS) occurs when polarizable particles in a sample are bathed in the oscillating electric field of a beam of light. The varying field induces oscillating dipoles in the particles and this radiate light in all directions. This important and universal phenomena is the basis for explaining why the sky is blue, why fog and emulsions are opaque and other observations. It has been utilized in many areas of science to determine particle size, molecular weight, shape, diffusion coefficients etc. With Brookhaven Laser Light Scattering System this rich field of exploration is open to you for both Dynamic Light Scattering (DLS) and Static Light Scattering (SLS).

In DLS the dynamics of the scattered light are determined and analyzed. The short-term intensity fluctuations (dynamics) of the scattered light arise from the fact that the scattering particles are going rapid thermal motions. These movements are called Brownian motion and they cause short-term fluctuations in the intensity of the scattered light. From the DLS measurements many interesting subjects may be explored, among them:

• Particle size distributions
• Particle aggregation phenomena
• Micellar systems
• Micro-emulsion technology
• Colloid behavior
• Vesicles & Liposomes
• Plasmid DNA’s
• Particle size growth
• Nucleation processes & Protein crystallization

In the SLS mode time-averaged instensity measurements are made -- at either or variable angles -- in the range from 8° to 130° and analyzed with software provided for the methods of Zimm, Berry, Debye, Guinier, Kratky etc. Such evaluations using measured angular or concentration dependencies of the intensity of the scattered light provide key information for those interested in the topics below:

• M_w Molecular weight determinations (dn/dc value must be known).
• Rg Radius of gyration (root mean square RMS radius- average distance of each point in a molecule from the molecule's center of gravity.
• A₂ Determination of second virial coefficient.
• Micro-emulsion technology.
• Colloid behavior.
• Complex fluid characterization.
• Emulsion polymerization.
• Particle size growth.
• Nucleation processes.