INHIBITION OF POSITRONIUM FORMATION AND ITS QUENCHING REACTIONS IN BINARY SOLID-SOLUTIONS AND MIXTURES OF METAL TRIS-2,2,6,6-TETRAMETHYL-3,5-HEPTANEDIONATE (DPM) COMPLEXES

The inhibition of positronium formation and its quenching reactions ha ve been studied in binary solid solutions formed by Al(dpm)(3) as a ma trix, and Co(dpm)(3), Fe(dpm)(3) and Mn(dpm)(3) as guest molecules, by lifetime and Doppler broadening spectroscopies. In all the solid solu tions studied the quenching of positronium lifetime by redox reactions was observed, The total inhibition and quenching rate constants deter mined for each system are similar. The full-width at half-maximum of t he annihilation line increases with increasing guest molecule mole fra ction, indicating the presence of redox reactions combining with inhib ition processes. The corresponding mixtures were studied as blanks.