Spectral Line Broadening and Shift
A spectral line extends over a range of frequencies, not a single frequency (i.e., it has a nonzero linewidth). In addition, its center may be shifted from its nominal central wavelength. There are several reasons for this broadening and shift. These reasons may be divided into two broad categories - broadening due to local conditions and broadening due to extended conditions. Broadening due to local conditions is due to effects which hold in a small region around the emitting element, usually small enough to assure local thermodynamic equilibrium. Broadening due to extended conditions may result from changes to the spectral distribution of the radiation as it traverses its path to the observer. It also may result from the combining of radiation from a number of regions which are far from each other.
Read more about this topic: Spectral Line
Famous quotes containing the words spectral, line, broadening and/or shift:
“How does one kill fear, I wonder? How do you shoot a spectre through the heart, slash off its spectral head, take it by its spectral throat?”
—Joseph Conrad (1857–1924)
“We are apt to say that a foreign policy is successful only when the country, or at any rate the governing class, is united behind it. In reality, every line of policy is repudiated by a section, often by an influential section, of the country concerned. A foreign minister who waited until everyone agreed with him would have no foreign policy at all.”
—A.J.P. (Alan John Percivale)
“Extensive traveling induces a feeling of encapsulation, and travel, so broadening at first, contracts the mind.”
—Paul Theroux (b. 1941)
“I will use the world and sift it,
To a thousand humors shift it,
As you spin a cherry.”
—Ralph Waldo Emerson (1803–1882)