INVESTIGATIONS OF THE RECOMBINATION OF O ATOMS WITH CO OVER THE LARGEST RANGE OF TEMPERATURE AND PRESSURE PRACTICABLE IN THE SHOCK TUBE (1); STUDY OF THE THERMAL DISSOCIATION OF HYDROGEN PEROXIDE AT TEMPERATURE ABOVE 1000 K (2); STUDY OF THE UNIMOLECULAR DISSOCIATION OF FORMALDEHYDE (3).

Abstract : The recombination reaction CO+O+M yields CO2+M was studied in incident and reflected shock waves from 1200 K to 2300 K. The recombination rate constant has a slightly negative apparent activation energy and confirms an unusual behaviour of the temperature dependence of the recombination rate constant. The unimolecular dissociation of hydrogen peroxide was investigated near the low pressure limit. Experiments at 20atm indicated the beginning of the fall-off region. In addition, light absorption corresponding to a species which forms and is consumed again during the reaction, was observed around 2300A. This absorption is possibly due to HO2. The thermal dissociation of formaldehyde at low concentrations in argon was investigated at temperatures 1400dissociation were important even at concentrations as low as 0.02 percent. The consequences of the measured rate constant on the values of the dissociation energies D(H-HCO) and D(H-CO) are discussed. (Author)