Spectroscopy and Energy Transfer Kinetics of the Interhalogens.
Final rept. Apr 83-Mar 84,
ILLINOIS INST OF TECH CHICAGO
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The electronic quenching of Br2 B by Br2 x and He was investigated in the gas phase. Non-linear self quenching plots revealed the presence of rapid energy transfer to predissociated levels. Quenching and rotational energy transfer rates of 4.2 x 10 to the 10th power and approx. 8 x 10 to the -10th power ccmolecules respectively were obtained by kinetic modeling. Near-resonant vibrational energy transfer also contributes to the deactivation process, and this occurs wtih a rate constant 3.5 x 10 to the 10th power ccmolecules. Electronic quenching of Br2 B by He was found to be slow k sub q 2 x 10 to the 12th power ccmolecules, but deactivation by rapid rotational and vibrational energy transfer k sub t 10 to the -10 power ccmolecules was observed. Gas phase electronic quenching of I2 B by He at 9.4K was studied in a free jet expansion. An effective cross section of 0.33 sq A was obtained, demonstrating a significant collision energy dependence for this parameter. Simple trajectory calculations show that this result is compatible with a collision induced predissociation model of the deactivation process. The HeBr2 Van der Waals complex was observed in a free jet expansion. The complex was detected by laser excitation of the bands associated wtih the Br2B - X system. Excitation spectra and polarization measurements provided insights into the excitation and relaxation mechanisms present in the matrix.
- Atomic and Molecular Physics and Spectroscopy