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)
“Anybody who’s been through a divorce will tell you that at one point ... they’ve thought murder. The line between thinking murder and doing murder isn’t that major.”
—Oliver Stone (b. 1946)
“The establishment of democracy on the American continent was scarcely as radical a break with the past as was the necessity, which Americans faced, of broadening this concept to include black men.”
—James Baldwin (1924–1987)
““Circumstantial evidence is a very tricky thing,” answered Holmes thoughtfully. “It may seem to point very straight to one thing, but if you shift your own point of view a little, you may find it pointing in an equally uncompromising manner to something entirely different.””
—Sir Arthur Conan Doyle (1859–1930)