Estimation of the decay rate of Be7 and Be27 encapsulated in C70
| Autor: | Alexander V. Nikolaev, Eugene V. Tkalya, A. V. Bibikov |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Physical Review C. 100 |
| ISSN: | 2469-9993 2469-9985 |
| Popis: | Electron capture ($\ensuremath{\beta}$-decay) rates of $^{7}\mathrm{Be}$ and $^{7}\mathrm{Be}_{2}$ encapsulated in ${\mathrm{C}}_{70}$ have been estimated by calculating the electron density $\ensuremath{\rho}(0)$ at the $^{7}\mathrm{Be}$ nucleus and comparing it with $\ensuremath{\rho}(0)$ and experimental $\ensuremath{\beta}$-decay rates of $^{7}\mathrm{Be}$ inside another fullerene---${\mathrm{C}}_{60}$. For that the endohedral fullerenes $^{7}\mathrm{Be}@{\mathrm{C}}_{70}$ and $^{7}\mathrm{Be}_{2}@{\mathrm{C}}_{70}$ have been examined by means of the ab initio approach using the Hartree-Fock method with the the second order M\o{}ller-Plesset perturbation theory accounting for the Van der Waals foces. Our calculations indicate that the $^{7}\mathrm{Be}_{2}@{\mathrm{C}}_{70}$ complex is stable with the binding energy of 1.3 eV and the $^{7}\mathrm{Be}$ dimer bond length 2.30 \AA{}. It has been found that $\ensuremath{\rho}(0)$ is practically the same in $^{7}\mathrm{Be}@{\mathrm{C}}_{70}$ and $^{7}\mathrm{Be}_{2}@{\mathrm{C}}_{70}$, but larger than in an isolated $^{7}\mathrm{Be}$ atom. The increase of $\ensuremath{\rho}(0)$ however is smaller than in $^{7}\mathrm{Be}@{\mathrm{C}}_{60}$. We also discuss in detail the mechanism underlying the increase of $\ensuremath{\rho}(0)$ and consequently the decrease of the decay rate in $^{7}\mathrm{Be}@{\mathrm{C}}_{70}$ in comparison with the isolated $^{7}\mathrm{Be}$ atom. |
| Databáze: | OpenAIRE |
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