## absorption cross-section, $$\sigma$$

https://doi.org/10.1351/goldbook.A00038
Molar Napierian @A00037@ divided by the @A00543@. When integrated against the logarithm of wavenumber (or frequency) it is called the integrated absorption cross-section.
Source:
Green Book, 2nd ed., p. 32 [Terms] [Book]