Characterization of gas-aerosol interaction kinetics using morphology dependent stimulated Raman scattering. 1992 Annual summary
This study is aimed at characterizing the influence of aerosol surface structure on the kinetics of gas-aerosol interactions. Changes in gas phase chemical reaction rates as a function of exposure to a specific aerosol are measured with aerosols having different surface properties due to the composition and/or temperature of the material making up the aerosol. The kinetic data generated can be used directly in atmospheric modeling calculations. The surface structure of the aerosol is using morphology-dependent enhancement of simulated Raman scattering (MDSRS). Detailed dynamics of gas-aerosol interactions can be obtained by correlating the change in the reaction rate with change in surface structure and by monitoring the change in aerosol surface structure during, the course of the reaction. This dynamics information can be used to generate kinetic data for systems which are similar in nature to those studied, but are not amenable to laboratory investigation. We show here that increased MDSRS sensitivity is achieved by using an excitation laser source that has a narrow linewidth and we have been able to detect sulfate anion concentrations much lower than previously reported. We have shown that the linewidth of the MDSRS mode excited in a droplet is limited by the laser linewidth. This is a positive result for it eases our ability to quantify the MDSRS gain equation. This result also suggests that MDSRS signal size should be independent of droplet size, and preliminary experiments confirm this hypothesis.
- Research Organization:
- Pittsburgh Univ., PA (United States). Dept. of Chemistry
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-92ER61480
- OSTI ID:
- 10142723
- Report Number(s):
- DOE/ER/61480-1; ON: DE93012324
- Resource Relation:
- Other Information: PBD: 30 Jan 1993
- Country of Publication:
- United States
- Language:
- English
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