POSITRONIUM INTERACTIONS IN AQUEOUS OXYACIDS AND HYDROGEN COMPOUNDS

The lifetimes of positrons in the oxyacid-water systems, H3PO4, H2SO4, HClO4, HNO3, and water, and in the hydrogen compound-water systems, HCl, HF, NH3, H2O2, and water, were determined. The short lifetime component (τ1), the long lifetime component (τ2), and the intensity (I2) of the long lifetime component were derived from the composite lifetime data. The connection between changes in I2, the solution composition, and hot radical reactions is discussed. Data are discussed in terms of a proposed oxidation of positronium (Ps) by H+ and of possible chemical reactions leading to compounds of Ps and some estimates of bond energies are made: PsO (2.2 ± 0.5 eV), PsOH (<1.5 eV), PsF (2.9 ± 0.5 eV), and PsCl (2.0 ± 0.5 eV). The unknown bond strength of O-Cl in ClO4- is estimated as 3.3 ± 0.5 eV.