Also contains definition of: molar decadic absorption coefficient
https://doi.org/10.1351/goldbook.M03972
@A00028@ divided by the absorption pathlength, \(l\), and the @A00295@, \(c\): \[\varepsilon(\lambda) = \frac{1}{c\, l}\, \text{lg}\! \left ( \frac{P_{\lambda}^{0}}{P_{\lambda}}\right ) = \frac{A(\lambda)}{c\, l}\] where \(P_{\lambda}^{0}\) and \(P_{\lambda}\) are, respectively, the incident and transmitted @S05828@.
Notes:
- The term @M03973@ for molar @A00037@ should be avoided.
- In common usage for \(l/\text{cm}\) and \(c/\pu{mol dm-3}\) (\(\text{M}\)), \(\varepsilon(\lambda)\) results in \(\pu{dm3 mol-1 cm-1}\) (\(\text{M}^{-1}\ \text{cm}^{-1}\), the most commonly used unit), which equals \(\pu{0.1 m2 mol-1}\) (coherent SI units).