quality quantification facet attenuation coefficient attenuation coefficient Linear decadic (a,K) and Napierian attenuation coefficients (α) are equal to the corresponding absorbances divided by the optical path length through the sample, but taking into account also the effects due to scattering and luminescence. The molar absorption coefficients (decadic ε, Napierian κ) are the linear absorption coefficients divided by the amount concentration. [IUPAC] IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). Online version (2019-) created by S. J. Chalk. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook. extinction coefficient