Cavity Ring-Down Spectrometer for the Absorption Measurements of Molecular Ions

摘要

The goal of this project was to develop an ion spectrometer capable of making absorption measurements on ions using cavity ring-down spectroscopy (CRDS). As part of our continuing goal of detecting ion products from ion- molecule reactions, we have successfully used CRDS to measure the vibronic absorption spectra of various small ions and radicals generated by a pulsed discharge nozzle. These spectra give information about the number densities and temperatures of the ions and radicals. Currently, our setup consists of a pulsed discharge nozzle that produces high concentrations of radicals and ions arranged perpendicular to the optical cavity made from two highly reflective mirrors. To date, we have obtained the absorption spectrum of N2(+) and CN as well as several atomic species.