An error due to inhomogenous distribution of absorbing species in the
analytical sample. It may be observed by probing the sample volume with an incident beam of radiation
of reduced cross-section.
Source:
PAC, 1988, 60, 1449
(Nomenclature, symbols, units and their usage in spectrochemical analysis - VII. Molecular
absorption spectroscopy, ultraviolet and visible (UV/VIS) (Recommendations 1988))
on page 1456