# 17-24-092

Napierian spectral absorption coefficient, <of a homogeneous non-diffusing layer>

an(λ)

quotient of the natural (Napierian) logarithm of the reciprocal of the spectral internal transmittance, τ(λ), of a layer of the medium and the length, l, of the path of a beam of radiation traversing that layer

where An(λ) is Napierian spectral absorbance.

Note 1 to entry: The Napierian spectral absorption coefficient is expressed in metre to the power minus one (m−1).

Note 2 to entry: This entry was numbered 845-04-85 in IEC 60050-845:1987.

Note 3 to entry: This entry was numbered 17-799 in CIE S 017:2011.

Publication date: 2020-12