reflectance, $ρ$

Also contains definitions of: reflectance factor, reflectivity

Fraction of incident radiation reflected by a surface or discontinuity, $ρ λ = P λ refl P λ 0$ , where $P λ 0$ and $P λ refl$ are, respectively, the incident and reflected spectral radiant power.

Note:

The reflectance for a beam of light normally incident on a surface separating two materials of refractive indices $n 1$ and $n 2$ is given by

$ρ λ = ( n 1 − n 2 ) 2 ( n 1 + n 2 ) 2$

Reflectance increases as the angle of incidence decreases from 90 degrees.

Source:

PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 413

Related index:

IUPAC > Gold Book > math/physics > quantities

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Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook.

Last update: 2014-02-24; version: 2.3.3.

DOI of this term: https://doi.org/10.1351/goldbook.R05235.

Original PDF version: http://www.iupac.org/goldbook/R05235.pdf. The PDF version is out of date and is provided for reference purposes only. For some entries, the PDF version may be unavailable.

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