Area under a
spectral band in an absorption spectrum where the absorption is linearly proportional to the amount of absorber in unit area.
Notes: - The area under a band in a transmittance spectrum is not linearly proportional to the amount of absorber.
- The absorption quantity is usually a Beer-Lambert absorption coefficient, but recently \(\tilde{\nu} \alpha_{\rm{m}}''(\tilde{\nu})\), the wavenumber times the imaginary part of local molar polarizability, has been used for neat liquids to correct for dielectric effects.
Source:
PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 662 (https://doi.org/10.1515/pac-2019-0203)