Photochemical generation of the optoacoustic effect: Performance report

Technical Report · Mon Dec 01 04:00:00 EST 1986

OSTI ID:6613346

Diebold, G J

Our research with the inverse optoacoustic effect has shown that the dependence of the acoustic signal on mole fraction of infrared active gas is not linear, as predicted by the conventional optoacoustic theory. This anomalous signal dependence has led us to investigate the optoacoustic effect with laser excitation which showed the nonlinear behavior in an even more striking manner than was found for the inverse effect. These findings have prompted us to investigate the mechanism of sound generation in gases especially as regards analyte concentration. In this report, we give a one dimensional model for the optoacoustic effect where the thin periodically heated layer of gas acts as a piston driving the remaining volume of gas. The dependences of the amplitude and phase of the acoustic signal on mole fraction of the absorbing gas and modulation frequency are shown to differ distinctly from those derived from the solution of the wave equation. Experiments with SF/sub 6/ at high concentration are reported that show the range of validity of the model.

• Research Organization: Brown Univ., Providence, RI (USA). Dept. of Chemistry
• DOE Contract Number: FG02-84ER13235
• OSTI ID: 6613346
• Report Number(s): DOE/ER/13235-T1; ON: DE87007763
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GASES
HALIDES
HALOGEN COMPOUNDS
LASERS
MATHEMATICAL MODELS
ONE-DIMENSIONAL CALCULATIONS
PHOTOACOUSTIC EFFECT
SULFUR COMPOUNDS
SULFUR FLUORIDES