Spectroscopy and Energy Transfer Kinetics of the Interhalogens.
Abstract
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 cc/molecule/s 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 cc/molecule/s. Electronic quenching of Br2 (B) by He was found to be slow (k sub q <2 x 10 to the 12th power cc/molecule/s), but deactivation by rapid rotational and vibrational energy transfer (k sub t >10 to the -10 power cc/molecule/s) 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 Br2(B - X) system. Excitation spectra and polarization measurements provided insights into the excitation and relaxation mechanisms present in the matrix.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1984
- Accession Number
- ADA160131
Entities
People
- M. C. Heaven
Organizations
- Illinois Institute of Technology