Schuster-Kubelka-Munk function

From the spectra of calcined solid samples, Schuster-Kubelka-Munk function was calculated at both 350 nm and 260 nm. The ratio of these functions versus Cf is displayed in Figure 4 with the purpose of showir the variation of the Mo(o) to Mo(t) ratio as a function of the solution concetrtration. Figure 4a shows that this ratio increases with molybdenum concentration in the AHM and PA solution, in a similar fashion to that of the increa.se of Ca. 

The reflectance spectra were recorded in the geometry R0,d (4) in the frequency range 5000-40,000 cm-1 in a previously described apparatus (4, 6). The absorbance is represented by the logarithm of the Schuster-Kubelka-Munk (SKM) function, F(RX) = (1 — RX)2/2RX, where Rx is the reflectance measured against a white standard. Since the comparison of the reflectance spectra with the transmission spectra of complexes in molecular sieves revealed that the scattering coefficient is a constant independent of the wavelength (4), the logarithm of the SKM function is, but for an additional constant, a correct representation of absorbance. 

DRIFT spectra are displayed according to the Schuster-Kubelka-Munk remission function, Eq. (28) ... 

The absorption spectrum of the fresh Pd/Al203 catalysts after reactional cycles are presented in Fig. 10.10. The Schuster-Kubelka-Munk (SKM) function,... 

As several researchers have shown empirically, the use of —log(reflectance) can provide, analogous to a transmittance measurement, a linear relationship between the transformed reflectance and concentration, if the matrix is not strongly absorbing as can be found for many samples studied by near-infrared spectroscopy. This issue is presented in detail below. A different approach based on a physical model was considered for UV/VIS measurements and later also applied within the mid-infrared. A theory was derived by Kubelka and Munk for a simple, onedimensional, two-flux model, although it must be noted that Arthur Schuster (1905) had already come up with a reflectance function for isotropic scattering. A detailed description of theoretical and practical aspects was given by Korttim. The optical absorption... 

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