Introduction To Scattering

Understanding Scattering

Scattering is a fundamental phenomenon whereby particles or waves deviate from their original trajectory owing to irregularities within a medium or interactions with other particles. This process is significant in several scientific disciplines, including physics, chemistry and astronomy.

Types of Scattering

There are several types of scattering, each characterised by the nature of the incoming particle or wave and its interaction mechanism:

Elastic Scattering

In elastic scattering, the kinetic energy of the particles or waves remains unaltered after the interaction. This method is employed to investigate the structural properties of materials.

Inelastic Scattering

In contrast, in inelastic scattering an energy transfer occurs between the incoming particle or wave and the target, resulting in a change in kinetic energy. This process yields information regarding the dynamic properties of materials.

Scattering of Electromagnetic Radiation

Electromagnetic radiation is scattered when electromagnetic waves, such as light, interact with particles. This interaction provides quantitative data on the size, shape and composition of the scattering particles.

Rayleigh Scattering

Rayleigh scattering occurs when the particles responsible for scattering are considerably smaller than the wavelength of the incoming electromagnetic radiation. Consequently, shorter wavelengths are scattered more efficiently, which results in the sky appearing blue.

Mie Scattering

Mie scattering occurs when the dimensions of the particles are comparable to the wavelength of the radiation. This scattering phenomenon is observed in white clouds, as all wavelengths undergo similar scattering.

Applications of Scattering

Scattering techniques are applied in various fields:

• Astrophysics: For determining the composition and distribution of celestial bodies.
• Medical Imaging: Techniques such as MRI and ultrasound utilise scattering principles.
• Material Science: For analysing the structural properties of materials at the microscopic level.

Further information is available at Stanford Advanced Materials (SAM).

Frequently Asked Questions

What is scattering in physics?

Scattering is the deflection of particles or waves from their initial path due to interactions with other particles or irregularities in a medium.

How does Rayleigh scattering affect the colour of the sky?

Rayleigh scattering results in shorter wavelengths of light, such as blue, being scattered to a greater extent than longer wavelengths, thereby producing a blue sky.

What is the difference between elastic and inelastic scattering?

In elastic scattering, the kinetic energy remains preserved, whereas in inelastic scattering an energy transfer occurs that alters the kinetic energy.

Where is Mie scattering most frequently observed?

Mie scattering is most frequently observed in phenomena such as white clouds and fog, where the particle size is comparable to the wavelength of visible light.

Why is understanding scattering important in materials science?

Scattering techniques enable the microscopic structural properties of materials to be analysed, which is beneficial for the development and characterisation of new materials.