## spectral (photon) effectiveness

https://doi.org/10.1351/goldbook.S05814
The reciprocal of the @[email protected], $$E_{\text{p}}^{0}$$, at @[email protected] $$\lambda$$, causing identical photoresponse, $$\Delta \text{y}$$, per unit time ($$\frac{\Delta \text{y}}{\Delta t}$$). The @[email protected] spectrum is directly proportional to the @[email protected] of the sensory pigment, if spectral @[email protected] is negligible.
Source:
PAC, 1996, 68, 2223. (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2275 [Terms] [Paper]