Sensitivity of the energy levels of singly ionized cobalt to the variation of the fine-structure constant

We use relativistic Hartree-Fock and configuration-interaction methods to calculate the dependence of transition frequencies for singly ionized cobalt on the fine structure constant. The results are to be used in the search for variation of the fine structure constant in quasar absorption spectra.

Figure 1

Energy levels of cobalt between 45 $\times$ 10${}^3$ cm${}^{-1}$ and 50 $\times$ 10${}^3$ cm${}^{-1}$ as functions of $(\alpha /{\alpha }_0){}^2$. Dotted line, $J=3$; short-dash line, $J=4$; long-dash line, $J=5$.

Figure 2

Energy levels of cobalt between 64.5 $\times$ 10${}^3$ cm${}^{-1}$ and 67.5 $\times$ 10${}^3$ cm${}^{-1}$ as functions of $(\alpha /{\alpha }_0){}^2$. Dotted line, $J=3$; short-dash line, $J=4$; long-dash line, $J=5$.

Figure 3

Energy levels of cobalt between 71 $\times$ 10${}^3$ cm${}^{-1}$ and 75 $\times$ 10${}^3$ cm${}^{-1}$ as functions of $(\alpha /{\alpha }_0){}^2$. Dotted line, $J=3$; short-dash line, $J=4$; long-dash line, $J=5$.