Breit-Pauli energy levels and transition rates for nitrogen-like and oxygen-like sequences

Breit-Pauli results for energy levels, lifetimes, and Landé gJ factors have been determined for all levels up to 2p23d of the nitrogen-like sequence ($Z=7$–17) and 2p33d of the oxygen-like sequence ($Z=8$–20). Exceptions are some lower members of the sequence where the spectrum included only those levels below the second 2p24s term in the case of N-like or 2p34s in the case of O-like. The computed energy and E1, E2, M1, M2 transition data between all levels, including convergence of the LS line strength for both length and velocity forms, may be viewed at a website. In this paper, critically evaluated transition data is presented for N I, O II, Mg VI, and Si VIII (N-like sequence) and O I, Ne III, Mg V, and Si VII (O-like) for E1 transitions including uncertainty estimates. The accuracy of energy levels is determined by comparison with experiment. Transition rates with uncertainties are compared with experiment and other theory

Atomic data and collisional-radiative model for beryllium and its ions

In this work we present a collisional–radiative model constructed for all ionization stages of beryllium. Convergent close-coupling, K-matrix and Coulomb–Born-exchange methods were applied to calculate the necessary atomic data. For the neutral beryllium atom a comparison of all methods is given. Fractional ion abundances, radiative power losses and electron cooling rates were calculated as functions of electron temperature. The comparison with other available data shows a rather good agreement

Calculations for electron-impact excitation and ionization of beryllium

The B-spline R-matrix and the convergent close-coupling methods are used to study electron collisions with neutral beryllium over an energy range from threshold to 100 eV. Coupling to the target continuum significantly affects the results for transitions from the ground state, but to a lesser extent the strong transitions between excited states. Cross sections are presented for selected transitions between low-lying physical bound states of beryllium, as well as for elastic scattering, momentum transfer, and ionization. The present cross sections for transitions from the ground state from the two methods are in excellent agreement with each other, and also with other available results based on nonperturbative convergent pseudostate and time-dependent close-coupling models. The elastic cross section at low energies is dominated by a prominent shape resonance. The ionization from the and states strongly depends on the respective term. The current predictions represent an extensive set of electron scattering data for neutral beryllium, which should be sufficient for most modeling applications