{"term":{"id":"14030","title":"out-scattering","longtitle":"IUPAC Gold Book - out-scattering","doi":"10.1351\/goldbook.14030","code":"14030","status":"current","synonym":"<em>synonym<\/em>: scattering out (out of the beam under consideration)","definitions":[{"id":1,"text":"Physical process by which the incoming electromagnetic radiation is forced to deviate from a straight trajectory by non-uniformities in the medium.","notes":{"1":"Physical phenomenon taking into account scattered radiative energy from the rays in the direction \\(\\mathit{\\Omega}\\) considered in the radiative transfer equation (RTE) into any direction \\(\\mathit{\\Omega}'\\).","2":"Mathematical definition: \\({\\rm{Sc}}_{\\rm{out}} = \\sigma_{\\lambda} (\\boldsymbol{x},t) L_{\\mathit{\\Omega},\\lambda} (\\boldsymbol{x},t)\\) where \\(\\boldsymbol{x}\\) is the coordinate in a three-dimensional space in the path of the beam, \\(t\\) is the time coordinate, \\(\\sigma_{\\lambda} (\\boldsymbol{x},t)\\) is the space- and time-dependent linear napierian scattering coefficient, \\(L_{\\mathit{\\Omega},\\lambda} (\\boldsymbol{x},t)\\) is the incident space- and time-dependent radiance in the direction \\(\\mathit{\\Omega}\\). SI unit is \\(\\pu{W sr-1 m-4}\\). Common unit is \\(\\pu{W sr-1 cm-3 nm-1}\\).","3":"The mathematical definition in photon terms is: \\({\\rm{Sc}}_{\\rm{out}} = \\sigma_{\\lambda} (\\boldsymbol{x},t) L_{\\rm{p},\\mathit{\\Omega},\\lambda} (\\boldsymbol{x},t)\\) with \\(L_{\\rm{p},\\mathit{\\Omega},\\lambda} (\\boldsymbol{x},t)\\) the incident space- and time-dependent photon radiance. SI unit is \\(\\pu{s-1 sr-1 m-4}\\) in photon number basis and \\(\\pu{mol s-1 sr-1 m-4}\\) in chemical amount basis. Common unit in photon number basis is \\(\\pu{s-1 sr-1 cm-3 nm-1}\\) and \\(\\pu{einstein s-1 sr-1 cm-3 nm-1}\\) in chemical amount basis."},"links":[{"term":"in-scattering","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/14023"},{"term":"radiative transfer equation","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/14077"}],"sources":["PAC, 2011, 83, 931. 'Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)' on page 962 (https:\/\/doi.org\/10.1351\/PAC-REC-09-09-36)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/14030\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/14030\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/14030\/plain"},"citation":"Citation: 'out-scattering' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351\/goldbook.14030","license":"The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/) for individual terms.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","disclaimer":"The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.","accessed":"2026-06-28T20:55:52+00:00"}}