Decomposition rates for H2, diluted in Ar, were studied behind incident shock waves over the temperature range 2900° to 4700°K. HCl and the infrared emission from this molecule were used in a manner to trace the course of decomposition of the H2. In terms of recombination rate constants, we found (cc, moles, sec units) k−3=1018T−1, k−4=2.5k−3, and k−5=20k−3, where the subscripts 3, 4, and 5 refer respectively to Ar, H2, and H as third bodies.

The dissociation of Cl2 in Cl2–Ar mixtures was measured in a shock tube over the temperature range 1700° to 2500°K. Direct absorption spectrophotometry was used to follow the course of the reaction. A rate constant given by k=8.90×1013 exp —48 300/RT cm3/mole-sec [or,alternatively,k=3.13×1012(57 080/RT)2.087exp−57 080/RT cm3/mole·sec]was found to fit the measured data over the entire temperature range with a most probably error of ±6%. The activation energy determined agreed exactly with that measured by Hiraoka and Hardwick although the over-all rate constants were a factor of 10 lower than those reported by these investigators. Recombination rate constants, calculated from the measured dissociation rate constants by use of the thermodynamic equilibrium constant, were found to be in good agreement with the theoretical predictions of Benson and Fueno.

The decomposition of HF in HF–Ar and HF–H2–Ar mixtures was studied behind incident shock waves over the temperature range 3800° to 5300°K employing infrared emission techniques. For HF dissociation, a rate k1=1019.053T−1 exp (−134 100/RT) or, alternatively, k1=1022.710×T−2 exp (−134 100/RT) was found to best represent the experimental data; the exchange rate for H+HF was found to be k2=1013 exp (−35 000/RT); the recombination rate for H2 was best represented by k−3=1018.30T−1 (all rates are in cubic centimeter—mole units). Rates derived for H–F recombination were found to be in good numerical agreement with the theory of Benson and Fueno.

Continuous laser action has been observed on several HF and DF vibrational-rotational transitions. The HF lases between 2.6 and 2.9μ and DF lases between 3.6 and 4.1μ. The lines are identified and the relative intensities are shown.

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