https://doi.org/10.1351/goldbook.D01605
The inverse of the @[email protected] If the decadic @[email protected], \(a\), is used, the depth of penetration (\(\frac{1}{a}\)) is the distance at which the @[email protected], \(P_{\lambda }\), decreases to one tenth of its incident value, \(P_{\lambda }^{0}\). If the Naperian @[email protected], \(\alpha \), is used, the depth of penetration (\(\frac{1}{\alpha } = \beta \) in this case) is the distance at which the @[email protected] decreases to \(\frac{1}{\text{e}}\) of its incident value.
See:
absorbance
, attenuance