Second-order MBPT results for the carbon isoelectronic sequence

The electric quadrupole (E2) and magnetic dipole (M1) transitions between the levels of the 1s 2 2s 2 2p 2 , 1s 2 2s2p 3 and 1s 2 2p 4 configurations have been investigated in the carbon isoelectronic sequence. The stationary second-order many-body perturbation theory (MBPT) was used to account for electron correlations. Relativistic corrections were included within the Breit-Pauli approximation. The E2 and M1 transition energies, line strengths and transition probabilities obtained in various approximations are compared with experimental values as well as with results of other theoretical calculations.