Spectral band

[1] More generally, spectral bands may also be means in the spectra of other types of signals, e.g., noise spectrum.

For example, it may refer to a radio band, such as wireless communication standards set by the International Telecommunication Union.

In nuclear physics, spectral bands refer to the electromagnetic emission of polyatomic systems, including condensed materials, large molecules, etc.

When the number of atoms is large, one gets a continuum of energy levels, the so-called "spectral bands".

The band spectrum is the combination of many different spectral lines, resulting from molecular vibrational, rotational, and electronic transition.