Chemistry

Mercury vapor lamp

Mercury vapor lamp



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Area of ​​Expertise - Electrical engineering

A mercury vapor lamp, also called a quartz lamp, is a gas discharge lamp. It consists of a closed housing with a UV-permeable exit window. Inside there are two electrodes between which an electrical discharge takes place in the mercury vapor. Thus the lamp produces ultraviolet radiation of wavelength 254 nm and (or) 313 and 366 nm.


Line width

the Line width is the width of the frequency or wavelength interval $ , Delta nu $ or $ , Delta lambda $, which is covered by a spectral line in a spectrum. The phenomenon was discovered in optical spectra, but also occurs in all spectra of any other type of radiation. In quantum physics (e.g. in the case of unstable elementary particles) the line width is also often determined by the energy uncertainty or "Decay width"$ , Gamma = h Delta nu ( equiv hbar Delta omega ) $, where $ h $ is Planck's constant, $ hbar = h / 2 pi $ and $ , omega = 2 pi nu $. Usually the full width at half maximum is given, i.e. & # 160h. the interval over the profile of the line under consideration in which the spectral intensity is greater than half the maximum value.

If the observed radiation originates from many independent sources, a distinction is made between them homogeneous line width, which every single issuer already has, from the inhomogeneous line widthwhich could be reduced by a more precise selection of the issuers. The causes of the homogeneous line width are, in addition to the fundamental energy uncertainty of all unstable systems, external disturbances such as collisions of the emitters and Doppler shifts due to their disordered movement.