Abstract

The application of high-resolution Fourier-transform spectroscopy (FTS) to the measurement of both absorption and emission spectra of radicals has grown greatly over the past 10, years with emphasis on the recording of line positions and the determination molecular parameters. Our primary motivation at the NOAA Aeronomy Laboratory for measuring infrared spectra of radicals by means of Fourier-transform spectroscopy is to obtain information that can be used to monitor these species, either in other laboratory experiments or in the atmosphere. This requires accurate determinations of both line positions and line intensities. Data on absolute line intensities of radicals, however, are limited. This is primarily a result of experimental limitations on our ability to produce radicals with a known concentration over a known path length. Recently developed, infrared spectral analysis methods eliminate the need for quantitative concentration measurements in determining line intensities provided that accurate relative line intensities and the dipole moment as a function of v are known. Fourier-transform spectroscopy is well suited to relative line-intensity measurements because the entire spectrum is recorded simultaneously, therefore minimizing possible systematic errors introduced by measuring a spectrum one line at a time. This talk will discuss the experimental techniques used to record spectra of radicals and will focus on experiments designed to obtain line intensities for radicals of atmospheric interest. Examples to be discussed include CIO, BrO, and OH radicals.

© 1990 Optical Society of America