title: Penetration of light into multiple scattering media: model calculations and reflectance experiments. Part II: The radial transfer.
abstract: In continuation of our contribution to "The Axial Transfer" (Appl. Spectr. 2012. 66(8): 934-943), this paper describes the distribution of localized incident radiation in multiple scattering layers of arbitrary thickness and analyzes the lateral intensity profiles of radiation leaving the sample from its illuminated and non-illuminated surfaces. The theoretical profiles are calculated with different approximations of the equation of transfer. We derive for both non-absorbing and absorbing layers simple analytical expressions and verify their accuracy and range of applicability by comparison with Monte Carlo simulations. Particular emphasis is given to the analysis of the radial absorption, an under-theorized and under-investigated feature that can help to identify weak or hidden absorbers. In addition, we contribute to the description of how the radial reflectance is affected by anisotropy or by error sources like multiple surface reflection for samples in glass cells or deflectance (sideway loss) of radiation in small samples. Finally, the theoretical results are compared with experimental data of radial reflectance for quasi non-absorbing and absorbing powder layers.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany. dieter.oelkrug@uni-tuebingen.de
authors.forename: Dieter
authors.initials: D
authors.lastname: Oelkrug
authors.forename: Manfred
authors.initials: M
authors.lastname: Brun
authors.forename: Peter
authors.initials: P
authors.lastname: Hubner
authors.forename: Karsten
authors.initials: K
authors.lastname: Rebner
authors.forename: Barbara
authors.initials: B
authors.lastname: Boldrini
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kessler