Diiodomethane (CH2I2) photolysis in the presence of ozone is a suggested precursor to new particle aerosol formation, particularly in coastal areas. As part of the PNNL database of gas-phase infrared spectra, the quantitative absorption spectrum of CH2I2 has been acquired at 0.1 cm-1 resolution. Two strong b2 symmetry A-type bands at 584 and 1114 cm-1 are observed, but are not resolved at 760 Torr and appear as B-type. In contrast, the b1 symmetry C-type bands near 5953, 4426 and 3073 cm-1 are resolved with rotational structure, including Q-branches with widths = 1 cm-1. The quantitative infrared and near-infrared vapor-phase spectra (600 - 10,000 cm-1) are reported for the first time and discussed in terms of ambient monitoring. FT-Raman spectra and ab initio calculations are used to complete vibrational assignments.
Revised: August 8, 2006 |
Published: February 17, 2006
Citation
Johnson T.J., T. Masiello, and S.W. Sharpe. 2006.The Quantitative Infrared and NIR Spectrum of CH2I2 Vapor: Vibrational Assignments and Potential for Atmospheric Monitoring.Atmospheric Chemistry and Physics 6, no. 9:2581-2591.PNNL-SA-47406.