Why is DLS used?

Applications for Dynamic Light Scattering DLS is most commonly used to analyze nanoparticles. Examples include determining nanogold size, protein size, latex size, and colloid size. In general, the technique is best used for submicron particles and can be used to measure particle with sizes less than a nanometer.

What is SLS and DLS?

In short, DLS measures how scattering changes over time, regardless of the amplitude (amplitude only matters for instrumentation optimisation), and SLS measures the amplitude of scattering, regardless of its fluctuations.

What is the principle of DLS?

The basic principle is simple: The sample is illuminated by a laser beam and the fluctuations of the scattered light are detected at a known scattering angle θ by a fast photon detector. Simple DLS instruments that measure at a fixed angle can determine the mean particle size in a limited size range.

What is light scattering method?

Light scattering belongs to a class of techniques known as area-integrating methods for measuring surface texture. Rather than relying on coordinate measurements of surface points, light scattering methods probe an area of the surface and yield parameters that are characteristic of the texture of the area as a whole.

How to calculate the scattering vector of a wave?

Scattering Vector k0= (2π/λ)u0 k1= (2π/λ)u1 Q = k1− k0 Q = (4πsinθ)/λ •Scattering vector essentially defines the magnification that can be achieved in the diffraction experiment •Waves from atoms separated by a vector r are out of phase by one cycle (2πphase angle or λ path length),

When does light hit small particles it scatters in all directions?

When light hits small particles, the light scatters in all directions (Rayleigh scattering) as long as the particles are small compared to the wavelength (below 250 nm). Even if the light source is a laser, and thus is monochromatic and coherent, the scattering intensity fluctuates over time.

How is the scattering vector used in diffraction?

•Scattering vector essentially defines the magnification that can be achieved in the diffraction experiment •Waves from atoms separated by a vector r are out of phase by one cycle (2πphase angle or λ path length), •constructive interference occurs when the scattering vector Q is parallel to r and Q equal to 2π/r.

Where does the dynamic information in light scattering come from?

The dynamic information of the particles is derived from an autocorrelation of the intensity trace recorded during the experiment. The second order autocorrelation curve is generated from the intensity trace as follows: where g2(q;τ) is the autocorrelation function at a particular wave vector, q, and delay time, τ, and I is the intensity.