Doppler broadening


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Doppler broadening

(dop -ler) Broadening of spectral lines due to the random motion of emitting or absorbing atoms. As a result of the Doppler effect, atoms moving away from the observer show lines with a slight shift to longer wavelengths; atoms moving toward the observer show a slight shift to shorter wavelengths. The overall effect is that the line is broader than the natural width (determined by quantum mechanical uncertainty).

The motion of the atoms may be due to thermal motion, in which case the effect is larger for lighter atoms. Turbulence of stellar material, rapid rotation of a star, or an expanding stellar atmosphere can also produce Doppler broadening. See also line broadening.

Doppler broadening

[′däp·lər ‚brȯd·ən·iŋ]
(spectroscopy)
Frequency spreading that occurs in single-frequency radiation when the radiating atoms, molecules, or nuclei do not all have the same velocity and may each give rise to a different Doppler shift.
References in periodicals archive ?
performed a direct measurement of self-Kerr nonlinear coefficient in a three-level lambda EIT medium in the presence of Doppler broadening by using a cavity scanning technique.
These magnetic moments are probably associated with different defects, the plausibility of which is supported by the unique behavior of the S parameter [28] in the depth-resolved Doppler broadening of PAS measurements of the Al-Co-doped ZnO film explained below.
The topic of his PhD was "The effect of Kerr non-linearity, Doppler broadening and spontaneous generated coherence on slow light propagation".
(ii) If the line has a predominant Doppler broadening, which has a Gaussian profile, the real width is given by:
Doppler broadening positron annihilation (DBPAT) provides direct information about core and valance electrons in (CR-39) due to radiation effects.
Investigations into the uptake of water by primers have also been carried out using the positron-based techniques of positron annihilation lifetime spectroscopy (PALS) and Doppler broadening energy spectroscopy (DBES).
A much-touted key safety feature of the pebble-bed design lies in the con figuration of the fuel, pebble-bed reactors actually use the U-238 as stopgap "control rod." When core temperatures pass a certain point, causing the uranium atoms in the fuel to vibrate more rapidly, the U-238 atoms offer a wider "profile" to the neutrons zipping around the reactor core--a phenomenon called "Doppler broadening." As the U-238 absorbs more of the neutrons, the chain reaction slows, shutting down the reactor.
(Unless otherwise noted, all uncertainties given in this paper are standard uncertainties, i.e., one standard deviation estimates.) Doppler broadening can be avoided if the transition is excited with two counter-propagating photons, as originally proposed by Bender et al.
The cyclic aging is performed on several samples at 26 kV with 8 h of power on and 16 h of power off for aging times of 6, 12 and 18 months and the samples were examined for defect characterization using both Doppler broadening and positron lifetime techniques.
In particular, the isotope selectivity enhancement can be achieved with the Doppler broadening reduction, through effective multistep resonance ionization transition [14-16].
Doppler broadening positron annihilation technique (DBPAT) provides direct information about the change of core and valance electrons in Polyallyl diglycol carbonate (CR-39).