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Methane monitoring by near infrared photoacoustic spectroscopy: The importance of relaxation phenomena

2005; Springer Science+Business Media; Volume: 125; Linguagem: Inglês

10.1051/jp4

1764-7177

Stéphane Schilt, J.-P. Besson, Luc Thévenaz,

Advanced Chemical Sensor Technologies

The importance of molecular relaxation in photoacoustic spectroscopy is discussed.The particular case of methane monitoring in dry oxygen using a 1.65-mm laser-based photoacoustic sensor is reported.The slow vibration-to-translation energy transfer occurring in this gas mixture results in a drastic reduction of the detection sensitivity.A quadratic response of the sensor to the methane concentration is also reported and explained by molecular relaxation effects.