DopplerBreitung
DopplerBreitung, often referred to in English as Doppler broadening, is the widening of spectral lines caused by the distribution of radial velocities of emitting or absorbing particles along the observer’s line of sight due to thermal motion. Each particle shifts the frequency of emitted or absorbed radiation by an amount proportional to its velocity, and the collective effect of many particles produces a broadened line rather than a sharp transition.
In non-relativistic regimes, the DopplerBreitung is well described by a Gaussian line profile. The standard deviation
Thus DopplerBreitung increases with temperature and decreases with particle mass; lighter species and higher temperatures produce
Applications of DopplerBreitung are widespread in spectroscopy, astrophysics, and plasma physics. It is used to infer