Rapid-scanning Fourier-transform infrared spectroscopy with photothermal beam-deflection (mirage effect) detection at the solid–liquid interface

Abstract

Photothermal beam-deflection (mirage effect) detection in the mid-infrared with a commercial scanning Fourier-transform infrared spectrometer has been used to characterize various solid–liquid interface and surface-bound species. The inherently unfavorable ambient noise level and relatively high Fourier (photothermal modulation) frequencies associated with commercial scanning instrumentation are compensated by the thermal and refractive properties of the liquid beam-deflection medium, which enhance the signal. Preliminary results described illustrate the potential of the technique for infrared (IR) studies of electrochemistry, catalysis, corrosion, and other surface modifications, as well as for polarized IR single-crystal spectra.