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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
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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. doi:10.1351/goldbook.
Last update: 2014-02-24; version: 2.3.3.
DOI of this term: doi: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 The PDF version is out of date and is provided for reference purposes only.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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