ELECTRONIC SPECTROSCOPY OF OXYGEN-ATOMS TRAPPED IN SOLID XENON

The electronic spectroscopy of oxygen atoms trapped in solid xenon are reported. Excitation of the solid between 220 and 260 nm leads to two main emissions centered at 3.35 and 1.65 eV, both of which arise from the same upper state. The excitations are assigned to charge-transfer absorptions in interstitial O(h) sites; the emitting state, which has a lifetime of 227 ns, is assigned to Xe+O-(1-SIGMA+). An avoided crossing between the ionic and covalent 1-SIGMA+ states, and differential solvation of these states, explains the main trends of the spectroscopy of XeO in the gas and condensed phases. Implications regarding ionic and covalent many-body surfaces are discussed.