Revisiting spontaneous Raman scattering for direct oxygen atom quantification

In this Letter, the counterintuitive and largely unknown Raman activity of oxygen atoms is evaluated for its capacity to determine absolute densities in gases with significant O-density. The study involves C mathvariant="normal">O 2 microwave plasma generate a self-calibrating mixture establish accurate cross sections /> 3 P ↔ 1 0 transitions. approach requires conservation stoichiometry, confirmed within experimental uncertainty by 1D fluid model. measurements yield σ J = stretchy="false">→<!-- → <mml:mn>5.27 ±<!-- ± mathvariant="normal">s mathvariant="normal">y : 0.53 mathvariant="normal">r mathvariant="normal">a mathvariant="normal">n mathvariant="normal">d 0.17 ×<!-- × <mml:mn>10 −<!-- − <mml:mn>31 width="thickmathspace" mathvariant="normal">c mathvariant="normal">m / 2.11 0.21 0.06 , detection limit estimated be 15 systems without other scattering species.