Electron attachment to N2O at pressures near one atmosphere

Electron attachment to N2O in pure N2O and in several mixtures has been studied by microwave conductivity at pressures to above 1 atm. Ionization was by pulse radiolysis. The values of effective two-body rate constant exceed those predicted by the usual two-step, three-body mechanism and in several cases exceed the value of 5.5 x 10-13 cm3/molecule sec attributed to the first step of such a mechanism. This behavior is interpreted in terms of an additional mechanism that is only significant at higher pressures. It is suggested that this mechanism involves attachment to van der Waals complexes of N2O with the other molecules. A near zero value of activation energy supports this mechanism. Certain quantitative aspects are discussed