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Title: Temperature dependence of collisional broadening and shift for the Kr 4 p 6 S 01→5 p [3/2] 2 electronic transition

Temperature scaling of collisional broadening parameters for krypton (absorber)4p6S01→<#comment/>5p[3/2]2electronic transition centered at 107.3 nm in the presence of major combustion species (perturber) is investigated. The absorption spectrum in the vicinity of the transition is obtained from the fluorescence due to the two-photon excitation scan of krypton. Krypton was added in small amounts to major combustion species such asCH4,CO2,N2, and air, which then heated to elevated temperatures when flowed through a set of heated coils. In a separate experimental campaign, laminar premixed flat flame product mixtures of methane combustion were employed to extend the investigations to higher temperature ranges relevant to combustion. Collisional full width half maximum (FWHM) (wC) and shift (δ<#comment/>C) were computed from the absorption spectrum by synthetically fitting Voigt profiles to the excitation scans, and their corresponding temperature scaling was determined by fitting power-law temperature dependencies to thewCandδ<#comment/>Cdata for each perturber species. The temperature exponents ofwCandδ<#comment/>Cfor all considered combustion species (perturbers) were−<#comment/>0.73and−<#comment/>0.6, respectively. Whereas the temperature exponents ofwCare closer to more » the value (−<#comment/>0.7) predicted by the dispersive interaction collision theory, the corresponding exponents ofδ<#comment/>Care in between the dispersive interaction theory and the kinetic theory of hard-sphere collisions. Comparison with existing literature on broadening parameters of NO, OH, and CO laser-induced fluorescence spectra reveal interesting contributions from non-dispersive interactions on the temperature exponent.

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Publication Date:
Journal Name:
Applied Optics
Page Range or eLocation-ID:
Article No. 1438
1559-128X; APOPAI
Optical Society of America
Sponsoring Org:
National Science Foundation
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