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.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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 ?

(b) Simulated absorption spectra for W absorber and bare W slab with normally-incident light of x-polarization ([theta] = [phi] = 0, i.e., electric field parallel to the x-axis).

A Nanostructure-Based High-Temperature Selective Absorber-Emitter Pair for a Solar Thermophotovoltaic System with Narrowband Thermal Emission

Analyzing the UV-Vis absorption spectra of Figure 4(a) and tests data in Table 2, we can find that the maximum absorption wavelengths of five groups of sample solutions are in the range of 410~430nm, and when [mathematical expression not reproducible], the maximum absorption wavelengths Am has a little small value.

Controllable Synthesis of Silver Nanoparticles Using Three-Phase Flow Pulsating Mixing Microfluidic Chip

The absorption spectra of all three sensitizers on the Ti[O.sub.2] films exhibited significantly hypsochromic shift and a broader full width at half maximum (fwhm) than absorption spectra measured in CH[Cl.sub.3] due to strong interactions between the dyes and Ti[O.sub.2] surfaces.

Novel Imidazole Substituted Bodipy-Based Organic Sensitizers in Dye-Sensitized Solar Cells

Caption: Figure 1: Absorption spectra of surface freshwater from three Karelian lakes, unfiltered (solid lines) and filtered (dashed lines).

Excitation-Dependent Fluorescence Quantum Yield for Freshwater Chromophoric Dissolved Organic Matter from Northern Russian Lakes

Figure 2 shows that the absorption spectra of ASA, DNA, Tm(III), DNA-ASA, DNA-Tm(III), Tm(III)-ASA complex, and Tm(III)-ASA-DNA system at a certain concentration were obtained using a UV-vis spectrometer.

Drug Effect of Thulium(III)-Arsenazo III Complex on Herring Sperm DNA

Caption: Figure 6: Near-infrared absorption spectra of ACV ointments, observed to 4000-10000 [cm.sup.-1].

Evaluation between the Usability and Physicochemical Property of Acyclovir Ointments

The absorption spectra from 500 nm to 2000 nm at room temperature of 3 at.% Tm, x at.% Y are shown in Figure 2(a).

Optical Spectra Properties and Continuous-Wave Laser Performance of Tm,Y:Ca[F.sub.2] Single Crystals

Huffman, "The infrared and ultraviolet absorption spectra of laboratory produced carbon dust: evidence for the presence of the [C.sub.60] molecule," Chemical Physics Letters, vol.

IR and UV/VIS Spectroscopic Characterization of the Higher Fullerene [C.sub.76]-[D.sub.2] for Its Quantitative and Qualitative Determination

Absorption spectra of DBM shows broad band with maximum at 343 nm, which is assigned to enolic [pi]-[pi]* transitions of the [beta]-diketone moiety.

Study of thermal and optical properties of dibenzoylmethane Eu(III) organic complexes

In this study, the absorption spectra of PSU (sample 9), PSU-b-PAO-b-PDMS (samples 1-5), and PSU-WAO (sample 6) in 1,2-dichloroethane were recorded at different temperatures and the relative absorbance [A.sub.max]/[A.sup.o] was calculated for each sample (where [A.sub.o] and Amax are the values of maximum absorbance at 20[degrees]C and at a given temperature, t, respectively, when the temperature varies from 25[degrees]C to 75[degrees]C).

Temperature influence on the behavior of polysulfone-b-poly(alkylene oxide)-b-poly(dimethylsiloxane) triblock copolymers in a selective solvent

Huber, "Coherent potential approximation for the absorption spectra and the densities of states of cubic Frenkel exciton systems with Gaussian diagonal disorder," Physica B: Condensed Matter, vol.

Absorption Spectrum and Density of States of Square, Rectangular, and Triangular Frenkel Exciton Systems with Gaussian Diagonal Disorder

UV-Vis absorption spectra of all synthesized CdSe nanoparticles are shown in Figure 1(a).

Enhancing Photocatalytic Degradation of Methyl Blue Using PVP-Capped and Uncapped CdSe Nanoparticles