The @R05046@ at @W06659@ \(\lambda \) per unit @W06659@ interval. The SI unit is \(\text{W m}^{-1}\), but a commonly used unit is \(\text{W nm}^{-1}\).
Source: PAC, 1996,
68, 2223. (
Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2276 [
Terms] [
Paper]