Longitudinal and transverse phonons velocities

In summary, the velocities of longitudinal and transverse phonons can be extracted from their equation of motion by taking the derivative with respect to time.
  • #1
Einj
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Hello everyone! Does anyone know how to extract the velocities of longitudinal and transverse phonons starting from their Lagrangian and/or equation of motion?

Thanks!
 
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  • #2
The velocities of longitudinal and transverse phonons can be extracted from the equation of motion by taking the derivative with respect to time. In general terms, the equation of motion for a phonon is given by:m*a(x) + f(x) = 0 Where m is the mass of the particle, a(x) is the acceleration, and f(x) is the force acting on the particle. Taking the derivative of this equation with respect to time will give you the velocity of the particle. The velocity will depend on the specific form of the force f(x), so the exact answer will depend on the specific system you are considering.
 

Related to Longitudinal and transverse phonons velocities

1. What are longitudinal and transverse phonons?

Longitudinal and transverse phonons are types of lattice vibrations or waves that occur in a solid material. Longitudinal phonons involve particles moving back and forth in the same direction as the wave, while transverse phonons involve particles moving perpendicular to the direction of the wave.

2. How are longitudinal and transverse phonons related to sound waves?

Longitudinal phonons can be thought of as sound waves in a solid material, as they involve particles moving in the same direction as the wave. Transverse phonons also contribute to the overall sound wave, but to a lesser extent.

3. What affects the velocities of longitudinal and transverse phonons?

The velocities of longitudinal and transverse phonons are affected by the material properties of the solid, such as density, stiffness, and temperature. They can also be affected by the crystal structure and arrangement of atoms in the material.

4. How are longitudinal and transverse phonons measured?

The velocities of longitudinal and transverse phonons can be measured using techniques such as Brillouin scattering, inelastic neutron scattering, and ultrasonic measurements. These methods involve analyzing the interactions between the phonons and other particles or waves.

5. What is the significance of understanding longitudinal and transverse phonon velocities?

Understanding the velocities of longitudinal and transverse phonons is important for studying the properties and behavior of solid materials. It can also help in the design and development of new materials for various applications, such as in electronics, energy storage, and structural materials.

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