A plot of a quantity related to the absorption (absorbance, cross section, etc.) multiplied by the quantum yield for the considered process against a suitable measure of photon energy, such as frequency, ν, wavenumber, σ, or wavelength, λ, e.g. the conversion cross section, σ φ, has the SI unit m 2.
See also: action spectrum, efficiency spectrum, spectral effectiveness
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2234 (https://doi.org/10.1351/pac199668122223)