Spectroscopic studies of molecular ions and radicals in the low frequency regime

点击翻译按钮获取中文摘要

Despite their short lifetimes, molecular ions and radicals are of great importance in numerous chemical processes such as combustion, semiconductor fabrication and polymerization. Although they drive the chemistry in these environments, their properties are not well characterized. A more complete understanding of the nature of isolated reactive intermediates is a first step for exploring their interactions with other molecules and their roles in chemical reactions. Thus, the accurate characterization of molecular ions and radicals has implications to our understanding of processes of economic importance such as combustion engines, to processes with global impact such as pollution control and to even larger scale processes such as those responsible for the evolution of the Universe. The main objective of this research program is to use high resolution microwave and infrared spectroscopy to derive accurate and detailed molecular information for ions and radicals. Fundamental properties such as structure are intrinsically linked to the molecule's potential energy surface and thus, the observed spectra are unique fingerprints by which to identify reactive species and probe their roles in various environments. Target molecules include short-lived species found in hydrocarbon flames (protonated alcohols), the Earth's atmosphere (peroxy radicals) and astronomical sources (carbon-based ions/radicals). The techniques used to characterize the ground state molecular parameters of reactive species are i) Fourier transform microwave (FTMW) and ii) chirped pulse-FTMW spectroscopy using custom-built instruments at the University of Manitoba. The low frequency bending and torsional motions of these moieties will be probed using iii) FT infrared spectroscopy at the far infrared beamline of the Canadian Light Source.