What are scattering losses?
Scattering is the redirection of the 'beam' of light, as is illustrated in the diagram below:



Source: University of Wisconsin

The description from the document Fundamentals of modern
UV-visible spectroscopy (Figure 46) states that


  Scattering causes an apparent absorbance because less light
  reaches the detector


They also detail two main types of scattering in UV spectroscopy (Figure 47):


  • Rayleigh scattering: Particles small relative to wavelength
  • Tyndall scattering: Particles large relative to wavelength