Researchers in Japan have found that the lifetime of radioactive beryllium-7 goes down by nearly 1% if it is caged inside a carbon buckyball (C60). While chemical shifts of nuclear decay rates have been known for a long time, they still come as a surprise to many people. Moreover, they are typically much smaller than 1%.
Tsutomu Ohtsuki of Tohoku University in Sendai, and colleagues there and at Yokohama National University, have measured the lifetimes for the isotope both in bulk metal and in carbon-60. They found a discrepancy of approximately 10 hours out of 53 days. Beryllium-7 decays by electron capture, so what the researchers are seeing are chemical effects on electrons that change their wavefunctions enough for them to spend significantly more time in the nucleus, and hence be prone to capture.
Further reading
T Ohtsuki et al. 2004 Phys. Rev. Lett. 93 112501.
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Compiled by Steve Reucroft and John Swain, Northeastern University