Kinetics of the termolecular reaction of gas phase Pd(a1S0) atoms with methane

The gas-phase removal rate constants for the reaction of ground state palladium (a1S0) with methane in argon buffer are reported as a function of total pressure and temperature. The pressure dependence indicates a termolecular mechanism. The limiting low-pressure third-order rate constant, k0, in argon buffer at room temperature is (2.0±0.7)×10−30 molecule−2 cm6 s−1. Second-order rate constants were measured at 20.0 Torr from 348 to 523 K. Derived third-order rate constants can be expressed as logk0(T)=−201.5+141(logT)−29(logT)2 over the temperature range 294–523 K.