Measurement of the pressure broadening coefficient of the 625 GHz transition of H2O2H2O2 in the sub-millimeter-wave region
Sato, T. O., et al. (2010). "Measurement of the pressure broadening coefficient of the 625 GHz transition of H2O2H2O2 in the sub-millimeter-wave region." Journal of Quantitative Spectroscopy and Radiative Transfer 111 6: 821-825
The hydrogen peroxide ( H 2 O 2 ) molecule plays an important role in stratospheric ozone chemistry as a reservoir molecule in the HO X cycle. The Superconducting Sub-Millimeter-Wave Limb Emission Sounder (SMILES) instrument in the Japanese Experiment Module (JEM) on the International Space Station monitors H 2 O 2 using the pure rotational J Ka , Kc = 20 1 , 19 – 19 2 , 17 transition at 625.044 GHz in the ground vibronic state. Accurate retrievals of H 2 O 2 abundances rely on a knowledge of pressure broadening effects for this transition, and the required nitrogen ( N 2 ) and oxygen ( O 2 ) broadening coefficients are measured here for the first time. Values of the pressure broadening coefficients, γ ( N 2 ) = 4.03 ± 0.06 MHz / Torr and γ ( O 2 ) = 2.49 ± 0.04 MHz / Torr are obtained at room temperature, with statistical 3 σ uncertainties given. The value for air broadening is then derived to be γ ( air ) = 3.71 ± 0.09 MHz / Torr , where the uncertainty includes possible systematic errors.