A measurement has been made of the electron impact ionization cross section of F2 and Cl2 over the energy range 15–100 V. Both species exhibit a maximum cross section at electron energies near 100 eV, the maximum values being approximately 1.5× 10−16 and 7.0× 10−16 cm2 for F2 and Cl2, respectively. The measurement in Cl2 fits an observed correlation between the maximum cross section and the square root of the polarizability. This correlation seems to apply to a wide variety of atomic and molecular species. Based on this correlation we estimate the polarizability of F2 to be approximately 8× 10−25 cm3

The vibrational relaxation of carbon monoxide by atomic oxygen has been measured behind incident shock waves in the temperature range of 1800–4000 °K. The atomic oxygen was produced by the rapid thermal decomposition of ozone. The experimentally derived relaxation times can be expressed in the form p τCO–O=exp(54 T−1/3−7.3) μsec·atm, which corresponds to a collisional probability of the order of 10−2 for the vibration-translation energy transfer. This is from two to three orders of magnitude larger than the probability for self-relaxation by CO over the same temperature range.

Shock-wave density profiles have been measured for each component in helium-argon mixtures over the argon mole fraction range from 0.011 to 0.87. The shock waves were produced by a shock holder in the flow field near the exit of a Mach 2 nozzle. The species densities were derived from spectrally resolved measurements of the radiation from gas atoms excited by an electron beam. The measured species density ratios across the shock waves agreed within 7% with each other and with theory. Diffusive separation of the mixture was observed within the shock wave and the helium was compressed upstream of the argon in all cases. No initial acceleration of the argon was observed for small argon mole fractions contrary to the continuum calculations of Sherman. Diffusion effects resulted in considerable broadening of the shock wave, and for argon mole fractions of 0.1 to 0.2 the maximum-slope thickness of the mixture was almost three times the corresponding value for a pure gas.

The vibrational relaxation in CO2–Ar, CO2–O2–Ar, and CO2–O–O2–Ar mixtures was studied over the temperature range 2000–4000°K. Infrared emission measurements were made of the 4.3 μ asymmetric stretch mode and the 2.7 μ combination bands. Since all the modes of CO2 have been shown to exhibit the same relaxation time, the present measurements could be directly related to the relaxation rate for the translation-vibration excitation excitation of the bending mode. The experimental results indicate that O-atoms are approximately an order of magnitude more efficient than Ar in the relaxation of the bending mode with a collisional probability of the order of 10−2 at 3000°K.

Rate constants for the reactions of ReO3− and (WO3)n=1,2,3− with Cl2 and NO2 have been measured in a drift tube/mass spectrometer apparatus from thermal energies (295°K) to ∼ 0.07 eV in the center of mass system. The rate constants for these reactions involving atom exchange agreed to within a factor of 2 with the theoretical orbiting rate constant of approximately 7 × 10−10cm3/sec for both reactants. ReO4− did not react with either NO2 or Cl2. Ordinary charge transfer was not observed, implying electron affinities in excess of 2.5 eV for these metal oxides. The mass-identified zero-field mobilities of these ions in Ar were measured at 295°K and were found to be 1.94, 1.67, 1.96, 1.50, and 1.20 cm2 V−1·sec−1 for ReO3−, ReO4−, WO3−, (WO3)2−, and (WO3)3−, respectively.