In some crystals the two transverse acoustic modes have exactly the same dispersion curve.

Firstly dominated by acoustic modes the spectrum showed the appearance of gravity modes with amplitudes strictly in line with the outburst.

Rick spent 2 weeks travelling the country and promoting the re-release performing in acoustic mode.

The density variations may be due to acoustic modes, such as phonons, magnetic modes, such as magnons, or temperature gradients.

From these only 3p are associated with the acoustic modes, the remaining 3p(q-1) are accommodated through the optical branches.

The Sun has very many acoustic modes that oscillate in the interior simultaneously, and the inversion of their frequencies can yield the rotation of the solar interior.

What was discourse like in this ancient acoustic mode?

- Acoustic Phonon: The charge carrier exchanges energy with an acoustic mode of the vibration of atoms in the crystal lattice.

The plus sign results in the so-called optical mode, and the minus sign to the acoustic mode.

In the optical mode two adjacent different atoms move against each other, while in the acoustic mode they move together.