What Is Beam Vibration?

For a system with multiple atoms in the surface cell (or unit grid), the frequency and characteristic polarization of the surface vibration mode can be determined by the lattice dynamics method under the effect of the simple harmonic force between atoms. Vector. Since the arrangement of atoms in the surface is still periodic, the surface lattice waves formed by the surface vibration modes are waves that propagate along the surface. Their corresponding energy quanta are called surface phonons. Their frequency is generally within the permissible range of the atomic vibration mode frequency in the body, because the surface can be regarded as a large and extensive defect, which is obtained by the force between the atoms on both sides of an interface in an infinite crystal becoming zero. According to the frequency-wave vector relationship of the surface vibration mode, the surface lattice waves can be divided into two types: one is the acoustic surface lattice wave, and the other is the optical frequency surface lattice wave. They have both longitudinal and transverse waves in a specific propagation direction Points.