Electron scattering with atomic oxygen has been studied using the $B$-spline $R$-matrix-with-pseudostates method. Cross sections for elastic scattering, excitation, emission, and ionization processes are presented. The excitation cross sections have been calculated for transitions between the $2s^{2}2p^4$ and $2s^{2}2p^{3}3l$ states of oxygen in the energy range from threshold to 200 eV. The present work differs from numerous previous studies due to the inclusion of a large number of pseudostates in the calculation. We included a total of 1116 spectroscopic bound, core-excited autoionizing, and target continuum states in the close-coupling expansion. The atomic oxygen structure model has been described by combining the multiconfiguration Hartree-Fock and the $B$-spline box-based multichannel methods. The inclusion of a large number of pseudostates representing the target continuum has a major impact, especially on the theoretical prediction of the excitation cross sections for many transitions at intermediate energies. A large reduction in excitation and emission cross sections has been noted due to the inclusion of coupling to the ionization continuum. The calculated cross sections are now in better agreement with available experimental results. The ionization cross sections for the ground $2s^{2}2p^4{}^{3}P$ and metastable $2s^{2}2p^4{}^{1}D$ and ${}^{1}S$ states are also presented. The electron-impact-induced emission cross sections for the $\left(2s^{2}2p^{3}3s\right){}^3{S}^o–\left(2s^{2}2p^4\right){}^{3}P$ (130.4 nm), $\left(2s^{2}2p^{3}3d\right){}^3{D}^o–\left(2s^{2}2p^4\right){}^{3}P$ (102.7 nm), $\left(2s^{2}2p^{3}3s^{\prime }\right){}^3{D}^o–\left(2s^{2}2p^4\right){}^{3}P$ (98.9 nm), and $\left(2s^{2}2p^{3}3s^{\prime \prime }\right){}^3{D}^o–\left(2s^{2}2p^4\right){}^{3}P$ (87.8 nm) transitions have been calculated and compared with the available experimental results.

Extensive calculations are reported for electron collision strengths, rate coefficients, and transitions probabilities for a wide range of transitions in Fe ii. The collision strengths were calculated in the close-coupling approximation using the B-spline Breit-Pauli R-matrix method. The multiconfiguration Hartree-Fock method in connection with adjustable configuration expansions and a semiempirical fine-tuning procedure is employed for an accurate representation of the target wave functions. The energy correction was also used in the scattering calculations by adding to Hamiltonian matrices prior to transformation to intermediate coupling. The spin-orbit interaction term was added to the final Hamiltonian matrices in scattering calculations. The close-coupling expansion contains 340 fine-structure levels of Fe ii and includes all levels of the $3d^{6}4s$, $3d^{5}4s^2$, $3d^7$, and $3d^{6}4p$ configurations, plus a few lowest levels of the $3d^{5}4s4p$ configuration. The effective collision strengths are obtained by averaging the electron collision strengths over a Maxwellian distribution of velocities at electron temperatures in the range from ${10}^2$ to ${10}^5$ K and are reported for all possible inelastic transitions between the 340 fine-structure levels. The present results are more extensive than the previous calculations and considerably expand the existing data sets for Fe ii, allowing a more detailed treatment of the available measured spectra from different space observatories. Comparison with other calculations for collision rates and available experimental radiative rates is used to place uncertainty bounds on our collision strengths and to assess the likely uncertainties in the existing data sets.

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Transition probabilities, electron excitation collision strengths, and rate coefficients for a large number of O iii lines over a broad wavelength range, from the infrared to ultraviolet, have been reported. The collision strengths have been calculated in the close-coupling approximation using the B-spline Breit–Pauli R-matrix method. The multiconfiguration Hartree–Fock method in combination with B-spline expansions is employed for an accurate representation of the target wave functions. The close-coupling expansion contains 202 O²⁺ fine-structure levels of the , , , and configurations. The effective collision strengths are obtained by averaging electron excitation collision strengths over a Maxwellian distribution of velocities at electron temperatures ranging from 100 to 100,000 K. The calculated effective collision strengths have been reported for the 20,302 transitions between all 202 fine-structure levels. There is an overall good agreement with the recent R-matrix calculations by Storey et al. for the transitions between all levels of the ground configuration, but significant discrepancies have been found with Palay et al. for transitions to the ¹ S ₀ level. Line intensity ratios between the optical lines arising from the − ¹ D ₂ transitions have been compared with other calculations and observations from the photoionized gaseous nebulae, and good agreement is found. The present calculations provide the most complete and accurate data sets, which should allow a more detailed treatment of the available measured spectra from different ground and space observatories.