A detailed study has been made of the mechanism of electronic energy transfer between a metastable argon atom and a nitrogen molecule. The transition involves the excitation of nitrogen to the C3Π state. The metastable energy of argon is sufficient to excite the v′ = 2 level of the C3Π state if the nitrogen is originally in its v″ = 0 vibrational level of the X1Σ state. It was found that (1) the v′ = 3 level was not excited, (2) the population of the v′ = 0 level was greatly enhanced with the excess energy going into rotational energy of the N2 molecule, (3) the relative intensities of the v′ = 0, 1, and 2 levels could not be predicted on the basis of the Franck—Condon factors, and (4) the collision cross section for the observed energy transfer is about 100 times greater than the argon—argon de-excitation cross section. It is shown that the enhanced rotational structure of the v′ = 0 level of the C3Π state can be explained from the viewpoint of a minimum amount of initial internal energy transferring to relative kinetic energy of the particles. The v′ = 1 and 2 levels did not show enhanced rotational structure. From a consideration of the carbon monoxide—argon system, it is shown that the Wigner spin-conservation rule governs the efficiency of the electronic energy transfer during collision. This condition applies regardless of whether or not the transitions are optically allowed.

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A shock tube has been employed to study the reaction between atomic oxygen and nitrous oxide in an excess of molecular oxygen. The temperature was varied from 1700° to 2300°K. The total gas concentrations ranged from 0.085 to 1.42×10−5 moles/cc. The atomic oxygen was generated by the thermal decomposition of ozone. The rate constant for the reaction between atomic oxygen and nitrous oxide is shown to be k2′+k2″ = (2.3±0.4)×1013 exp(−25 000±800/RT) cc/mole sec. It is shown that the best fit to the experimental data is obtained when the extrapolation of the low-temperature rate constant for the reactionO+NO+M⇌NO2+M,is employed rather than the rate constant obtained through the reverse reaction and the equilibrium constant. The former rate constant is a factor of 6 greater than the latter rate constant.

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The rate of dissociation of carbon dioxide has been measured in the temperature range 3000°—5000°K. The amount of carbon dioxide was varied from 1% to 10% in a diluent of argon or nitrogen. The concentration of the mixture was varied from 0.11×10−5 to 0.49×10−5 mole/cc. It is shown that the decrease in temperature and increase in density caused by the endothermic dissociation must be considered in the analysis of the data. A computer program was employed to account for the effect of the changes in temperature and density on the observed rate of dissociation. The rate constants for the reaction CO2+M→CO+O+Mwere determined to be k1,Ar=7.11×1011T12exp(−84 500/RT) cc/mole·secwith argon as the diluent and k1,N2=5.33×1011T12exp(−79 600/RT) cc/mole·secwith nitrogen as the diluent. The probable dissociation mechanism also is discussed.