Tilt Angle from SNIFTIRS Spectra

Calculation of the Tilt Angle from SNIFTIRS Spectra 

SNIFTIRS spectra do not allow direct determination of the tilt angles of adsorbed molecules because of the superposition of the bands of molecules in the adsorbed state onto the bands of molecules desorbed into the thin-layer cavity. In order to determine the tilt angle, one has to calculate the absorbance for the adsorbed film  

For this purpose, the absorbance of desorbed molecules 2.3/ e( i) has to be determined independently. The subscript exp in I —— ) emphasizes that this is 

The spectrum of molecules in the desorbed state can be calculated using the following equation  

Once the quantity 23Fe E2) is known, the angle between the transition dipole and the surface normal can be determined using Eq. (44). However, this requires additional calculation of the hypothetical spectrum of randomly oriented adsorbed molecules 2.3/ e(E2)ran given by the equation 

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