It is the purpose of this project to measure the thermodynamic and physical-chemical properties of Antarctic stratospheric cloud particles. These polar stratospheric clouds (PSC's) are believed to be made up of nitric acid, hydrochloric acid and water, and they are almost certainly play very important roles in the destruction of ozone over Antarctica. The grantees will manufacture equilibrium solids in the laboratory under near- stratospheric conditions using classical physical-chemical techniques, based on controlled partial freezing of carefully prepared solutions. The vapor pressures and thermodynamic properties, such as heats of vaporization, will be measured directly using diode laser spectroscopy. The work is considered to be crucial for better understanding of the chemistry that takes place on the PSC particles.
