Ab initio calculation of electric quadrupole and magnetic dipole transitions in ions of the N I isoelectronic sequence

The electric quadrupole (E2) and magnetic dipole (M1) transitions in the ni trogen isoelectronic sequence (Z = 10-30) between the levels of the ls(2)2s (2)2p(3), ls(2)2s2p(4) and ls(2)2p(5) configurations are investigated. The results include wavelengths and radiative E2 and M1 transition probabilitie s. The stationary second-order many-body perturbation theory (MBPT) was use d to account for the electron correlations. A non-local potential was used to calculate the radial part of the effective Hamiltonian. Relativistic cor rections were included in the Breit-Pauli approximation. The lowest-order c orrelation corrections to the one-body part of the spin-orbit interaction o perator were also included.