Fraction of incident radiation reflected by a surface or discontinuity,
are, respectively, the incident and reflected spectral radiant power
The reflectance for a beam of light normally incident on a surface separating
two materials of refractive indices
is given by
Reflectance increases as the angle
of incidence decreases from 90 degrees.
PAC, 2007, 79, 293
(Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006))
on page 413
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