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]
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 electronic absorption spectra of PPa and PPME in DMF are shown in Fig.
Thus, the absorption spectra of standard solutions of CL of different concentrations (Table 6) were obtained.
On the basis of the results obtained, few conclusions can be made: (1) UV/VIS absorption spectra showed that PVA/CdS nanocomposites to display an absorption excitonic band around the range 350-390 nm, which was considered blue shift relative to the absorption peak of bulk CdS (515 nm).
The peak at shorter wavelengths (at ~441 nm) was also the peak on the absorption spectra of extracts for all feathers except the single reddest feather.
Tokyo, Japan, June 2, 2006 - (JCN Newswire) - The National Institute of Advanced Industrial Science and Technology (AIST; Hiroyuki Yoshikawa, President) and Tohoku University (Takashi Yoshimoto, President) have theoretically and experimentally analyzed the crystal nucleation process and the subsequent crystal growth process in the colloidal synthesis of CdSe quantum dots, and succeeded in clarification of the relationship among crystal size, crystal structure, and optical absorption spectra in the primary process of the crystal growth.
Solvent effects on the UV-Visible absorption spectra of several types of porphyrins and metalloporphyrins have been investigated previously in limited solvent sets (Nalliah 1995; Wicks 1994; Renge 1993; Renge 1991; Findsen et al.
The absorption spectra of chlorophyll in plants is a rich source of information about the state of the microorganism (9).
Human tissues contain a variety of substances whose absorption spectra at NIR wavelengths are well defined.
Because of their absorption spectra, however, hemoglobin variants and some derivatives of normal hemoglobin may interfere with pulse oximeter measurement (2, 5).
Seoul, Korea) has patented modified phytochrome A (PHYA) nucleic acid molecules in which Pr absorption spectra have been shifted to longer wavelength (i.
Figure 1 shows the absorption spectra of UVA1 and UVA2 in non-donor solvents.
The origin of these color differences is manifested in their absorption spectra.