Spectroscopic data is often represented by a spectrum.
Spectroscopy is used in physical and analytical chemistry as atoms and molecules have unique spectra. As a result, these spectra can be used to detect, identify and quantify the atoms and molecules. It is a broad field and includes many types, such as: absorption spectroscopy, emissions spectroscopy, infrared spectroscopy, gamma-ray spectroscopy and nuclear magnetic resonance. Spectral measurement devices are referred to as spectrometers, spectrophotometers, spectrographs or spectral analyzers. In these instruments, high purity gases are used as purge, zero or detector gases, and high accuracy gas mixtures are used for instrument calibration.