| The dissociation and relaxation of CO2 has been reexamined in the incident shock wave with the laser-schlieren technique. These new experiments covered 1377-6478 K, and 42-750 torr, and the new improvements have permitted accurate determination of both rate and incubation time. In general the steady rate measurements are in agreement with other recent determinations. The one anomaly is that the new rates are not fully second order; they vary about 50% over 70-600 torr. Relaxation times are in agreement with available literature, and incubation time to relaxation time ratios lie between 1.5 and 3 over 4000-6600 K, consistent with findings for other molecules. In a separate study, the dissociation of acetone was examined at high temperatures, 1429-1936 K, and over a wide range of pressure, 28-717 torr, in using the LS technique. There is no evidence of an incubation delay prior to the steady dissociation as the vibrational relaxation in this molecule is extremely fast. The combination of high temperature and low pressure makes possible observation of a strong unimolecular fall-off in this large molecule and the full parameterization of a restricted rotor Gorin model RRKM fit. The dissociation was successfully modeled using an extensive chain reaction mechanism. The ethane dissociation mechanism, developed in a previous study by Kiefer et al., was successfully tested here in the reverse direction as methyl recombination formed important part of the overall chain sequence. |
