Reflectance Techniques for Surface Photochemistry Studies

DIFFUSE REFLECTANCE TECHNIQUES FOR SURFACE PHOTOCHEMISTRY STUDIES 

1 Ground-State Diffuse Reflectance Absorption Spectra (UV-Vis-NIR) 

Kubelka and Munk [8] established that, for an ideal diffuser and optically thick samples (all those where a further increase in thickness does not change the reflectance of the sample), the reflectance is given by 

(6) the factor 2 takes into account the average increase of distance travelled by the excitation light inside the ideal diffuser. In the Kubelka-Munk theory the radiation is only regarded as scattered when it is backward reflected into a hemisphere whose boundary plane lies perpendicular to the x-direction [8c]. 

The remission function varies linearly with the number of absorbing chro-mophores in the solid sample, which are considered as being uniformly distributed. K and S are independent of the light penetration into the sample. For optically thick samples we have 

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