spectral radiant exitance, \(M_{\lambda}\)

https://doi.org/10.1351/goldbook.S05825
The @R05041@, \(M\), at @W06659@ \(\lambda \) per unit @W06659@ interval. The SI unit is \(\mathrm{W}\ \mathrm{m}^{- 3}\), but a commonly used unit is \(\mathrm{W}\ \mathrm{m}^{- 2}\ \mathrm{nm}^{- 1}\).
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2276 [Terms] [Paper]