Absorptivity


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Related to Absorptivity: Molar absorptivity

absorptivity

[əb‚sȯrp′tiv·əd·ē]
(analytical chemistry)
The constant a in the Beer's law relation A = abc, where A is the absorbance, b the path length, and c the concentration of solution. Also known as absorptive power. Formerly known as absorbency index; absorption constant; extinction coefficient.
(thermodynamics)
The ratio of the radiation absorbed by a surface to the total radiation incident on the surface.

Absorptivity

 

(or absorptive power), αv, the fraction of a monochromatic radiation flux of frequency v that is absorbed by a body on which the flux is incident. Although often called the absorption factor, it differs from the absorption factor in that it applies only to radiation of a specific frequency. The absorption factor is the integral of the absorptivities over all the frequencies present in the irradiating flux. The absorptivity for thermal radiation is dependent not only on the frequency or wavelength of the radiation but also on the temperature T of the body:

α = α(ν, T) = α*(λ, T)

REFERENCE

Landsberg, G. S. Optika, 4th ed. Moscow, 1957. (Obshchii kurs fiziki, vol. 3.)
References in periodicals archive ?
It is impossible to extract only the reflectivity of a particle, assign it to a geometric bounding surface, and at the very same time, ignore the absorptivity of this same particle.
Using the ratio of absorptivity and emissivity ([alpha]/[epsilon]) it was possible to estimate the selectivity.
Ultrasonic velocity, density, viscosity, relaxation time, attenuation coefficient, absorptivity of binay mixture of aniline in methanol at 300.
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This mode of heat transfer is different from the other two in that the wavelength of the thermal radiation, the direction or orientation from a radiating surface, and the geometric arrangement of two surfaces exchanging radiation are important considerations as are unfamiliar properties such as emissivity, absorptivity, reflectivity, and transmissivity.
The fluctuations in the laser beam energy absorption can be influenced by the periodic nature of the laser beam or the changes in the material's absorptivity.
The content of conjugated dienes were expressed as absorptivity at 232 nm of 1% oils in 2,2,4-trimethylpentane.
Absorptivity is a variable which play an important role in this process, as it directly influences the material transferred energy amount.
WTM also had to have good thermal stability and low absorptivity, since the measurements are performed using a high-power laser.
If both the molar absorptivity and concentration of the dye solution are known and closely controlled, which is the case with the MVS, the law can be used to determine an unknown pathlength traversed by a photometric light beam.
Given the lower response of the secoiridoids at 280 nm, due to their lower absorptivity and the incomplete resolution of all of the peaks, the ratio of the M-H peaks for the compounds in the MS traces was used to assess the relative abundance of the individual compounds (with oleuropein set as 100).