absorption spectrum


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absorption spectrum:

see spectrumspectrum,
arrangement or display of light or other form of radiation separated according to wavelength, frequency, energy, or some other property. Beams of charged particles can be separated into a spectrum according to mass in a mass spectrometer (see mass spectrograph).
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absorption spectrum

A spectrum that is produced when electromagnetic radiation has been absorbed by matter. Typically, absorption spectra are produced when radiation from an incandescent source, i.e. radiation with a continuous spectrum, passes through cooler matter. Radiation is absorbed (i.e. its intensity is diminished) at selective wavelengths so that a pattern of very narrow dips or of wider troughs – i.e. absorption lines or bands – are superimposed on the continuous spectrum.

The wavelengths at which absorption occurs correspond to the energies required to cause transitions of the absorbing atoms or molecules from lower energy levels to higher levels. In the hydrogen atom, for example, absorption of a photon with the required energy results in a ‘jump’ of the electron from its normal orbit to one of higher energy (see hydrogen spectrum).

The absorption lines (or bands) of a star are produced when elements (or compounds) in the outermost layers of the star absorb radiation from a continuous distribution of wavelengths generated at a lower level in the star. Basically the same elements occur in stars. Since each element has a characteristic pattern of absorption lines for any particular temperature (and pressure) range, there are several different types of stellar spectra depending on the surface temperature of the star. See spectral types. See also emission spectrum.

Absorption Spectrum

 

the spectrum that results when optical or X-radiation is passed through a substance and is selectively absorbed.

absorption spectrum

[əb′sȯrp·shən ‚spek·trəm]
(spectroscopy)
A plot of how much radiation a sample absorbs over a range of wavelengths; the spectrum can be a plot of either absorbance or transmittance versus wavelength, frequency, or wavenumber.
References in periodicals archive ?
The absorption spectrum of each solution was recorded and stored as data base.
Recent attempts to compensate for nonselective and selective scattering and to obtain the correct absorption spectrum are described by Merzlyak (21).
Moreover, solutions prepared from the tablet brands exhibited similar absorption spectrum, an indication that the tablet excipients and manufacturing methods did not affect its absorption.
The absorption spectrum of the neutral species is strongly red shifted relative to that of the parent cinnamic acid.
Working in the dark with a dim green light source, we packed plant tissue from the seedlings into the sample cell and measured the absorption spectrum.
This absorption spectrum allows us to determine the value of alpha with high accuracy.
The UV--vis absorption spectrum of the undoped PANT-OH and PANI-OH doped with boron trifuoride acid are shown in Fig.
It is evident that the absorption spectrum of the photoresist with 10% Ag colloid is similar at the unmodified grating and has no changes in the part of the spectra characteristic for Ag nanoparticles (Fig.
Optical absorption spectrum at near infrared peak of samples was obtained by infrared furrier transformation method.
However, attempts to analyze HCT directly using a derivative technique were futile, because of marked interference with EPR in its absorption spectrum.
Effects of interaction among different configurations in one of these cases are theoretically investigated, and a formula is obtained that describes the behavior of absorption spectrum intensity.
A mid-infrared absorption spectrum is generated when infrared radiation interacts in an appropriate manner with the molecular vibrations of a sample.