spectral fluence rate, \(E_{\lambda ,o}\)

https://doi.org/10.1351/goldbook.ST07479
Derivative of @FT07376@, \(E_{o}\), with respect to @W06659@, \(\lambda\). SI unit is \(\text{W m}^{-3}\); common unit is \(\text{W m}^{-2}\ \text{nm}^{-1}\).
Note:
All spectral terms may also be defined as derivatives with respect to frequency, \(\nu\), or wavenumber, \(\tilde{\nu}\), and are referred to, when necessary, as in terms of @W06659@, or frequency or wavenumber, respectively.
Source:
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 423 [Terms] [Paper]