Spectrophone Measurements in Sulfur Hexafluoride,
Abstract
Short pulses (approx. 1 microsecond) of 10.6 radiation from a CO2 laser have been used to generate optoacoustic pulses in gaseous SF6. The optical path length for 10.6 microns radiation in SF6 is very short at intermediate pressures (approx, 1 Torr) so a strong acoustic pulse is generated which travels in the direction of the incident laser beam (in addition to cylindrical expansion). As the gas pressure is decreased, the optical path length increases resulting in an acoustic pulse with a shape dominated by collisional transfer in SF6. As the pressure is lowered further (approx. 200 mTorr), thermal conduction to the test cell walls and spontaneous radiation by the excited gas become important. As these mechanisms begin to compete with slow collisional energy transfer processes, the optoacoustic signal changes in sign. A microscopic description of the behavior is included. Keywords: Vibrational energy transfer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1985
- Accession Number
- ADA172154
Entities
People
- Henry E. Bass
- Manaf H. Ali
Organizations
- University of Mississippi