Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Concentration Modulation Spectroscopy With a Pulsed Slit Supersonic Discharge Expansion Source

Published

Author(s)

S Davis, M Farnik, D Uy, David Nesbitt

Abstract

Frequency modulated discharges are combined with pulsed slit supersonic expansions to provide an intense, long path source of jet-cooled radicals/molecular ions for direct absorption laser spectroscopy. The high modulation frequency (100 kHz) permits lock-in detection of the modulated absorbance signals at sensitivities down to 7.3 x 10-7absorbance/Hz1/2 (within 40% of the shot noise limit) and provides excellent discrimination for radical or molecular ion spectra in the presence of much higher precusor concentrations. The sensitivity of these methods is demonstrated with direct absorption spectral data on sample jet-cooled molecular ions (H+3) and hydrocarbon radicals (CH3CH2).
Citation
Chemical Physics Letters
Volume
344
Issue
No. 1-2

Keywords

absorbance signals, direct absorption laser spectroscopy, Frequency modulated discharges

Citation

Davis, S. , Farnik, M. , Uy, D. and Nesbitt, D. (2001), Concentration Modulation Spectroscopy With a Pulsed Slit Supersonic Discharge Expansion Source, Chemical Physics Letters (Accessed April 24, 2024)
Created July 31, 2001, Updated October 12, 2021