ABSOLUTE NUMBER DENSITY MEASUREMENTS OF HYDROPEROXYL RADICAL IN A NANOSECOND PULSE DISCHARGE USING CAVITY RING-DOWN SPECTROSCOPY

Frederickson, Kraig

Permalink

https://hdl.handle.net/2142/100527 Copy

Description

Title

ABSOLUTE NUMBER DENSITY MEASUREMENTS OF HYDROPEROXYL RADICAL IN A NANOSECOND PULSE DISCHARGE USING CAVITY RING-DOWN SPECTROSCOPY

Author(s)

Frederickson, Kraig

Contributor(s)

• Adamovich, Igor V.
• Miller, Terry A.

Issue Date

06/21/18

Keyword(s)

Spectroscopy as an analytical tool

Abstract

A recently implemented cavity ring-down spectrometer has been used to perform absolute number density measurements of hydroperoxyl radical (HO$_{2}$) generated in a repetitive nanosecond-duration, pulse discharge sustained in a mixture of H$_{2}$/O$_{2}$/Ar. The probe source for the spectrometer is a custom-built, injection-seeded, optical parametric oscillator emitting an idler beam in the 1500 nm region accessing the first overtone (2$\nu$$_{1}$) of the O-H stretch. Water vapor was used as a standard species to characterize the spectrometer and provide estimates of the spectral linewidth, sensitivity, and noise level. A specially constructed ring-down cell, with the central portion consisting of rectangular quartz channel tubing and a pair of copper plate electrodes, was used to produce a repetitively pulsed discharge in a H$_{2}$/O$_{2}$/Ar mixture. Narrow bandwidth cavity ring down spectra are acquired of a hydroperoxyl absorption feature composed of numerous closely spaced ro-vibrational lines centered at 6638.20 \wn and number density is determined from the resulting spectral line. This is believed to be the first detection and quantitative measurement of hydroperoxyl radical produced in a nanosecond pulse discharge. The measured number density is compared to the value predicted by the kinetic model of a nanosecond pulse discharge in a reacting H$_{2}$/O$_{2}$/Ar mixture.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/100527

DOI

10.15278/isms.2018.RH02

Owning Collections