The temperature dependence of electron attachment to N2O in the gas phase

Abstract

The temperature dependence of electron attachment to N₂O has been measured in the gas phase for pure N₂O and N₂O–C₂H₆ and N₂O–neopentane mixtures. The rate constant found for e⁻+N₂O→N₂+O⁻ can be expressed as 2.2×10⁻⁷ exp(−5.18×10³/T) cm³/molecule⋅sec while that for e⁻ +N₂O→N₂O^−* is 4.2×10⁻⁹ exp(−2.65×10³/T) cm³/molecule⋅sec. The corresponding activation energies are 0.44 and 0.23 eV. The latter value is discussed by reference to recent calculations on the N₂O⁻ energy surface. Formation of N₂O^−* with such an activation energy seems possible. The temperature dependences of other reactions in the overall mechanism are also determined. Certain rate constants increase with a decrease in temperature. Formation of negative ion complexes is suggested to account for the observation.