Electronic bridge process in ${}^{229}\mathrm{Th}$${}^{+}$

We have studied the effect of atomic electrons on the nuclear transition from the isomeric ${}^{229m}\mathrm{Th}$ state to the ground ${}^{229g}\mathrm{Th}$ state in ${}^{229}\mathrm{Th}$${}^{+}$ due to the electronic bridge process. The exact value of the nuclear transition frequency is unknown so far; therefore, we have developed a formalism that can be used for any nuclear transition frequency. We have calculated positions of several high-lying even-parity states which are not presented in experimental atomic spectra databases. We have found their energy levels and $g$ factors.

Figure 1

Feynman diagrams of the EB process. The single and double solid lines relate to the electronic and the nuclear transitions, correspondingly. The dashed line is the photon line.