Change of 7Be decay rate in exohedral and endohedral C60 fullerene
A. Ray, P. Das, S.K. Saha, J.J. Das and N. Madhavan
Variable Energy Cyclotron Center, IN
nuclear decay rate, fullerene
We have measured the change of decay rate of 7Be in different environments including in atomic clusters such as fullerene C60. It has been found that the decay rate depends on the geometrical position of implanted 7Be in the atomic cluster. So the method can be used as a tool to determine the geometry of endohedral 7Be@C60 and exohedral 7Be-C60 complexes.
The half-life of 7Be implanted in a C60 fullerene pellet and gold foil has been measured to be about the same within 0.2%. Using a radiochemical technique, we measured that the probability of formation of endohedral 7Be@C60 by nuclear implantation technique was about 5.6%. Earlier work showed that the half-life of endohedral 7Be@C60 was about 1.2% shorter than that of 7Be in Au. An analysis of these results using LMTO method indicates that most of the implanted 7Be ions in fullerene C60 stay at distance of about 0.53 nm from the center of nearest C60 molecules forming exohedral complexes and those forming endohedral complexes go to the centers of fullerene cages.
Similarly the decay rate of 7Be in a large biomolecule will depend on its geometrical position. In future, this kind of study might also tell us about any abnormal change of DNA molecule in a living cell.
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Nanotech 2006 Conference Program Abstract