The error in
absorbance which may occur if there is a difference between the (mean)
wavelength of the radiation entering the sample cell and the indicated
wavelength on the
spectrometer scale.
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