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Photoacoustic Spectroscopy of Gaseous and Condensed Matter

A brief historical account of photoacoustic (PA) effect is followed by a simple mathematical model for the generation of PA signals due to nonradiative transitions in atoms and molecules. Some experimental setups, with microphone and piezoelectric transducers, are described for recording PA spectra of gaseous, solid, and liquid samples. Applications of PA spectroscopy in the investigation of harmful chemicals are presented with illustrative examples. The principle of photoacoustic imaging (PAI) is discussed along with examples of molecular imaging of biological tissue and internal organs in small animals.