Total internal reflectance optoacoustic spectroscopy
When radiation undergoes total internal reflection at a solid--gas interface, an exponentially decaying wave, known as the evanescent wave, propagates into the gas. If the incident radiation is amplitude modulated and the gas has an absorption at the wavelength of the radiation, the optoacoustic effect can be produced by absorption of energy from the evanescent wave. Experiments with 10.6 ..mu.. radiation internally reflected in an NaCl prism show the amplitude of the optoacoustic signal (in SF/sub 6/) to be linearly proportional to the product of the square of the electric field amplitude and the penetration depth of the evanescent wave as given by Fresnel's equations. The amplitude of the optoacoustic signal in a 100-..mu..l detection cell is found to increase linearly with the mole fraction of SF/sub 6/ in He over the range from 10/sup -5/ to 10/sup -2/.
- Research Organization:
- Brown University, Department of Chemistry, Providence, Rhode Island 02912
- OSTI ID:
- 6056819
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 54:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PHOTOACOUSTIC SPECTROMETERS
REFLECTIVITY
ELECTRIC FIELDS
ENERGY ABSORPTION
FREQUENCY DEPENDENCE
FRESNEL COEFFICIENT
GASES
INFRARED RADIATION
INTERFACES
MODULATION
PRISMS
SODIUM CHLORIDES
SOLIDS
SULFUR FLUORIDES
WAVE PROPAGATION
ABSORPTION
ALKALI METAL COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
ELECTROMAGNETIC RADIATION
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
INFRARED SPECTROMETERS
MEASURING INSTRUMENTS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SODIUM COMPOUNDS
SPECTROMETERS
SULFUR COMPOUNDS
SURFACE PROPERTIES
440300* - Miscellaneous Instruments- (-1989)