Positron annihilation in synthetic zeolites (II) magnetic quenching effect

Positron lifetime spectra were re-measured for a series of synthetic zeolites using a large time window of observation. Magnetic quenching experiments were also performed for the zeolites, and it has been confirmed that both the ₄ and the ₃ components are due to o-Ps. The annihilation rate of the third component, ₃, showed a good correlation with the size of the largest voids, which is similar to the correlation reported for other compounds. However the annihilation rate of the longest-lived component, ₄, showed a poor correlation with the void size. The ₃ component has thus been assigned to o-Ps in the regular voids of the zeolites, and the ₄ component to that escaped to inter-particle open spaces.