An Imaging Study Of The Photodissociation Of Ozone In The Huggins Band And O(1D) Reaction And Deactivation

Abstract

Velocity mapped imaging (VMI) is used to study the photodissociation and reaction dynamics in both single and crossed molecular beams. In this dissertation the focus of these techniques is on questions of atmospheric importance but the results also contribute to an understanding of reactions that take place by multiple pathways. The first part of the dissertation focuses on the dissociation of ozone in the Huggins band. Velocity - mapped images and O(3P2) yield spectra are analyzed to determine the relative O2 electronic and vibrational populations and to provide an estimation of the rotational population as characterized by a temperature. O2 images are also obtained to gain insight into the REMPI detection of O2 and the spectroscopy of the two lowest Rydberg states of O2, d 1[PI]g and C 3[PI]g. The second part of the dissertation describes the development of a crossed molecular beam apparatus. The apparatus allows for the use of VMI techniques for deactivating and reactive collisions with state-selective detection methods. Initial results for the electronic deactivation of O(1D) to ground state O(3P) on collision with O2 and N2 are reported. Within the dual-beam apparatus, a delayed detection method is developed to minimize background. In the final part of the dissertation, the vibrational and rotational distribution of NO from the O(1D) + N2O reaction is determined through analysis of the NO spectra between 220 - 246nm. An explanation is suggested for the differences in NO vibrational distribution observed in our apparatus compared to those of others who have also investigated this reaction.