Knowledge Bank

A technique has been developed for obtaining broad range scans of jet-cooled radicals using cavity ringdown spectroscopy. The talk will describe a method that uses a slit jet expansion in tandem with an electrical discharge to produce the reactive intermediates and obtain rotational temperatures of 15-30 K and effective vibrational temperatures of 0 K. The spectrum can be recorded by scanning the second stokes of an H$2$ Raman shifted YAG-pumped dye laser with bandwidth of $\approx$ 0.1 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$. This technique has been used to obtain the jet-cooled $A~-X~$ spectra of the NO$3$ radical and the 2,1-hydroxypropyl peroxy radical (2,1-HPP). Obtaining the jet-cooled spectra helped to identify hot bands present in the room temperature spectrum of NO$3$ and also helped to identify cold, low-frequency fundamental bands present in the 2,1-HPP spectrum.