Gas Phase Oxygen Quenching Studies of Ketone Tracers for Laser-Induced Fluorescence Applications in Nitrogen Bath Gas |
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Authors: | V. M. Shelar G. Umesh G. Jagadeesh K. P. J. Reddy |
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Affiliation: | 1. Optoelectronics Laboratory, Department of Physics , National Institute of Technology , Karnataka, Surathkal, Mangalore , India;2. Department of Aerospace Engineering , Indian Institute of Science , Bengaluru , India |
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Abstract: | 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 (ksv) and quenching rate constants (kq) 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. |
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Keywords: | diffusion coefficient fluorescence quenching ketones LIF oxygen |
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