Gas Phase Oxygen Quenching Studies of Ketone Tracers for Laser-Induced Fluorescence Applications in Nitrogen Bath Gas

• Published in: Spectroscopy letters Vol. 47; no. 1; pp. 12 - 18
• Main Authors: Shelar, V. M., Hegde, G. M., Umesh, G., Jagadeesh, G., Reddy, K. P. J.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 02.01.2014
• Subjects: Acetone; diffusion coefficient; Fluorescence; fluorescence quenching; ketones; Lasers; LIF; Low pressure; Mathematical analysis; Methyl ethyl ketone; oxygen; Quenching; Tracers
• ISSN: 0038-7010; 1532-2289
• DOI: 10.1080/00387010.2013.775463

In this paper we report the quantitative oxygen quenching effect on laser-induced fluorescence of acetone, methyl ethyl ketone, and 3-pentanone at low pressures (∼700 torr) with oxygen partial pressures up to 450 torr. Nitrogen was used as a bath gas in which these molecular tracers were added in different quantities according to their vapor pressure at room temperature. These tracers were excited by using a frequency-quadrupled, Q-switched, Nd:YAG laser (266 nm). Stern-Volmer plots were found to be linear for all the tracers, suggesting that quenching is collisional in nature. Stern-Volmer coefficients (k sv ) and quenching rate constants (k q ) were calculated from Stern-Volmer plots. The effects of oxygen on the laser-induced fluorescence of acetone, methyl ethyl ketone, and 3-pentanone were compared with each other. Further, the Smoluchowski theory was used to calculate the quenching parameters and compared with the experimental results.