Electron-induced synthesis of ozone in a dioxygen matrix

Ozone (O-3) was synthesized in the condensed phase induced by electron bombardment of multilayer films of molecular oxygen condensed at temperatures below 30 K on metal surfaces. O-3 formation was demonstrated by the observation of the asymmetric stretching (nu(3)) and bending (nu(2)) normal modes of vibration in a high-resolution electron energy-loss spectroscopy experiment, and by characteristic changes in electron-stimulated desorption of O-. The threshold electron energy for the O-3 formation is found at 3.5 +/- 0.2 eV. It corresponds to the formation of O(P-3) associated with O-(P-2) by dissociative electron attachment at condensed O-2, followed by the third body reaction O + O-2+ O-2 --> O-3 + O-2. Above 5.1 eV bombarding energy, dissociative excitation of the O-2* (c(1) Sigma(u)(-),C-3 Delta(u),A(3) Sigma(u)(+), B-3 Sigma(u)(-) states is the main source of atomic oxygen O(P-3) or O(D-1)involvedin the O-3 synthesis.