Band spectrum
A band spectrum is a spectrum of electromagnetic radiation that consists of many closely spaced (for atomic gases ) or overlapping spectral lines (for molecular gases). Such a sequence of spectral lines is also called a spectral band .
Examples of band spectra are the emission spectra or absorption spectra of excited gases that consist of several elements.
Band spectra are e.g. B. the emission spectra of the polar lights ( nitrogen and oxygen ), but also the emission spectra of the gases of the solar corona ( solar flare ). If the excited gases are in front of a body that emits a continuous spectrum (e.g. the surface of the sun), absorption band spectra are obtained from the excited gases in front of it.
The atomic emission spectrometry (AES) for example, uses the band spectra (linear low) by means of an extremely hot helium plasma as an energy source ( inductively coupled plasma ICP) produced by the sprayed solutions of unknown compositions, for the simultaneous quantitative determination of contained elements (multi-element analysis). The band spectra are split up by means of a diffraction grating and the most undisturbed spectral lines of the elements sought are used.