抄録
Axial velocity distribution in an I2-seeded Ar free jet is investigated by the laser-induced fluorescence(LIF)technique using a ring dye laser with 500 kHz line width. Since the translational temperature in the flow region is low, the hyperfine structure due to the nuclear spin of I2 molecules is observed in the spectrum of I2 B-X bands. The spectrum shape is explained by the quantum mechanical theory and the simulated spectra coincide with our measurements. First, the possibility of the translational temperature measurement based on the hyperfine spectrum shape is discussed. Then, axial velocity measurement is performed and the results are found to be in good agreement with those of Ashkenas & Sherman. The applicability and the velocity resolution limit of our measurement technique are also discussed.
