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 ?
According to (49)-(52), the calculation of the absorption spectrum is reduced to averaging over the distribution of the effective hyperfine field for all trajectories of motion of magnetizations of sublattices given by the values [bar.m](j).sub.1z] (E, m) and [[bar.m].sup.(j).sub.2z](E, m) with weight factors (48a) and (48b), which are defined by the excitation spectrum of antiferromagnetic particles (Figures 2 and 4).
The absorption spectrum of the investigated molecule contains one broadband in the visible region of the spectrum (Figure 2).
Figure 4 shows the UV-Vis absorption spectrum of the copper nanoparticles sample with a typical absorption plasmon band at approximately 560 nm.
Increase in the NPs concentration was observed at 1064nm followed by rise in the peak of absorption spectrum. On the contrary the ablation efficiency reduced at the green wavelength (532 nm) due to photo-fragmentation process where the high photons energy were absorbed by NPs colloidal, consequently the amount of photons that were focused at the immersed titanium plate reduce [21].
Although Bao and Bawendi detailed the general steps taken to create the CQD filters, their paper does not formally discuss the concentrations of the quantum dots used for each filter and how this relates to the absorption spectrum (2).
The dynamic quenching only affects the excited state of quenching molecule with no function on the absorption spectrum of quenching substances, whereas a complex of HSA and drug forms in static quenching, so there will be some changes in the spectra of the HSA [17].
The absorption spectrum measured with a Perkin Elmer Lambda 12 spectrometer was characterized by two broad absorption regions in the red and blue-violet range, with no distinct absorption maxima.
The absorption spectrum of all four prepared samples recorded over the 300900 nm range with a UV-VIS-NIR spectrometer is shown in Figure 3.
One approach in optimizing the efficiency of DSSCs is by making cocktail dye (mixing two or more dyes) to increase the absorption spectrum of the dyes [7, 8].
From Figure 2, it can be seen that absorption spectrum has a peak observed at around 250 nm, which is due to sliver ion.