Measurement of Electronic and Resonance Raman Spectra from the Same Gas Matrix or Thin Film Sample

Abstract

A new method is described to measure effective electronic absorption spectra by means of the Raman spectrometer. The spectra originate from the same sample spot of a gas matrix or thin film that was used for the Raman measurement. The influence of the substrate material and the angle of incidence was investigated. Octaethylporphinatocobalt (II) was used to demonstrate the method. It was observed that the α and β absorption bands shift as much as 700 cm⁻¹ depending on sample preparation, thermal treatment, and the resulting physical state. A variation of the angle of incidence from α = 45° to α = 20° had no influence on the position of the α and β bands. Five significantly different resonance Raman spectra were recorded with 514.5 nm excitation. It was found that the relative intensities of the Raman bands were dependent on the position of the β band with respect to the frequency of the exciting radiation. This result led to the conclusion that Raman band intensities should only be correlated with an effective electronic absorption spectrum obtained from the same sample spot.