Student Summer Scholars


Pressure broadening of carbon monoxide infrared absorption lines by neon

First Advisor

Stephanie Schaertel, George McBane


pressure broadening, carbon monoxide collisions, diode laser spectroscopy



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Carbon monoxide (CO), a deadly gas, is able to absorb infrared light that is invisible to the human eye. This absorption occurs at specific wavelengths that correspond to changes in energy levels in the molecule. We measure how the absorption of infrared light is affected if the CO molecules are also colliding with another gas. Specifically, we measure absorption spectra of mixtures containing both CO and neon (Ne). Ne is an inert gas that does not absorb the infrared light, but the addition of the Ne causes the CO to absorb a wider range of wavelengths. Using a set of increasing Ne pressures, we determine how sensitive the absorption widths are to the neon pressure, and characterize this sensitivity with a pressure broadening coefficient. These coefficients can be computed from a theory of Ne-CO collisions, so our experiment can be used to test theoretical collision models. Theoretical collision models are used to predict chemical reaction rates.