The full width at half maximum peak-height. The natural line width is the theoretical value of the full width at half maximum of the @N04241@, usually calculated from @L03515@ data.
Source: PAC, 1976, 45, 211. (Nomenclature and Conventions for Reporting Mössbauer Spectroscopic Data) on page 213 [Terms] [Paper]
Cite as: IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook.