A Study of the Interaction between the HOO radical and some small Molecules

Abstract: The HOO radical is a key intermediate in the atmosphere and is involved in a large number of reactions, including ozone loss cycles in the stratosphere and oxidation processes in the troposphere. This theses is a study of the HOO radical and its interactions with a number of small molecules that are present in the atmosphere. The HOO complexes were formed on the surface of growing argon matrices at 17 K. They were identified with FTIR spectroscopy in the mid infrared region utilizing H to D spectral shifts, concentration dependencies and photolysis experiments. In some of the spectra there were large amounts of potentially interesting non-identified bands. In order to assign the bands to common species statistical methods were used. Correlation coefficients were estimated between decay or growth curves from photolysis experiments and principal component analysis was performed on data matrices of the spectra. The infrared spectra of the identified complexes were compared with spectra of related complexes in the literature. From the shifts of the vibrational fundamentals, structures of the HOO complexes are discussed. The results from the spectroscopic measurements were compared with results from ab initio calculations. There is good accordance between the results. The HOO radical tends to form cyclic structures, which were observed with ClO2, CO, CO2 and SO2. The HOO radical is non-linear and when possible acts as a lone pair donor in the terminal oxygen and simultaneously forms a hydrogen bond.