Electron capture beta decay of Be-7 located inside and outside the C-36 fullerene

Equilibrium positions of the Be-7 atom both inside and outside the C-36 fullerene are found and the electron density at the Be-7 nucleus, rho(0), for these positions are calculated using a high-accuracy ab initio post-Hartree-Fock method. If Be-7 is located outside the C-36 cage the electron density at the Be-7 nucleus practically coincides with rho(0) of a single Be-7 atom. In the encapsulated Be-7@C-36 case rho(0) is found to lie close to the electron density rho(0) of the Be-7(2+) ion with the unoccupied 2s electron shell, which results in the smallest value among all known Be-7-based compounds where the influence of chemical environment on the probability of electron capture by Be-7 has been investigated. Consequently, the Be-7 half-life in the Be-7@C-36 molecular complex is expected to be the largest.