Temperature and impurity dependence of the vibrational collision number for O2−H2, O2−He, and O2−CO2 systems between 300°–675°K

Abstract

The oxygen vibrational collision number for three binary systems (O2−H2, O2−He, and O2−CO2) has been measured between 300°–675°K at low impurity concentration using an acoustic resonant technique. For the pure oxygen case extrapolated from the O2−He system, for instance, the experimental vibrational collision numbers follow closely the curve derived from the Parker's theory [J. G. Parker, J. Chem. Phys. 34, 1763 (1961)] and high temperature (> 1700°K) shock tube data [R. G. Millikan and D. R. White, J. Chem. Phys. 39, 3209 (1963)]. However, our experimental data disagree strongly with the shock tube data trend below 1700°K. The experimental vibrational collision numbers for the binary systems have been found in good agreement with Parker's theoretical prediction. A new data analysis technique has been developed to sort out the ever-elusive background loss in the resonant chamber resulting in a more reliable number for the molecular absorption at low impurity concentrations. [Work supported by NASA under Contract Number NAS7-100.]