Photoacoustic Spectrometry Coupled with Total Internal Reflection Technique: Theory and Experiment

Abstract

Theoretical expressions of photoacoustic signals generated in liquid in normal and oblique incidences of a laser beam are derived by modifying the Rosencwaig and Gersho theory for the investigation of distribution profiles of light absorbing species at solid-liquid interfaces. Expressions for both incidences show that the photoacoustic signal magnitudes are dependent on instrumental, solvent and thermal diffusion factors. The results expected from the expressions are in agreement with experimental results. This modified theory is expected to be applicable to liquid samples with any transparency.