Ab initio relativistic many-body calculation of hyperfine splittings of C 113 d+

This work presents accurate ab initio determination of the hyperfine splitting for the ground state and a few low-lying excited states of C 113 d+, an important candidate for the frequency standard in the microwave region, using the coupled-cluster theory in the relativistic framework. The hyperfine energy splittings, which are estimated here theoretically in the literature, are in good agreement with the recent experimental results. We have also carried out the lifetime calculations of the 5 P2 1/2 and 5 P2 3/2 states, which are in good agreement with the available experimental results. The role of different electron correlation effects in the determination of these quantities are discussed and their contributions are presented. © 2008 The American Physical Society.