Knowledge Bank

Research at Stanford to apply a tunable diode laser to measurements of CO in combustions gases will be described. Absorption spectroscopy with a diode laser provides a simple non-intrusive diagnostic which can be used for in-situ measurements of species concentration, temperature, and spectroscopic parameters such as line strength and collision width in post-flame gases. To infer CO concentrations form absorption measurements in flames, the temperature of the gases and the band strength at a reference temperature must be known accurately. The fundamental band strength of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}C16O$ was determined to be $283\pm 4$ $cm-2$ $atm-1$ at 273.2 K in a series of room temperature absorption cell experiments. The diode laser has also been used to measure collision widths of individually resolved vibration-rotation lines in the $1\leftarrow 0,2\leftarrow 1$ and $3\leftarrow 2$ bands of CO in the combustion products of an atmospheric pressure $CH4$- air flame on a flat flame burner.