Change of ~7Be Decay Rate in Exohedral and Endohedral C_(60) Fullerene

摘要

The half-life of exohedral ~7Be-C_(60) complex and that of ~7Be implanted in a gold foil have been found to be about the same within ≈0.2%. Using a radiochemical technique, we also measured that the probability of formation of endohedral ~7Be@C_(60) complex by nuclear implantation technique was (5.6±0.45)%. We also find that the half-life of endohedral ~7Be@C_(60) complex is shorter than that of exohedral complex by more than 1%. An analysis of these results using linear muffin-tin orbital method calculations indicates that most of the implanted ~7Be ions in fullerene C_(60) stay at a distance of ≈5.3 Angstrom from the centers of nearest C_(60) molecules forming exohedral compounds and those who enter the fullerene cages go to the centers of the cages forming endohedral ~7Be@C_(60) compounds.