Oscillator strengths and electron collision rates for fine-structure transitions in OII

Electron impact excitation collision strengths for the fine-structure transitions between the lowest 13 levels of the 2s(2)2p(3), 2s2p(4), and 2s(2)2p(2)3s configurations and from these levels to the next 22 other lowest levels of the 2s2p(4), 2s(2)2p23s, and 2s(2)2p(2)3p configurations have been calculated using a 62-level Breit-Pauli R-matrix approach with orthogonal radial functions and a 47-level Breit-Pauli R-matrix approach with nonorthogonal radial functions. A B-spline basis has been used for the description of continuum functions, and no orthogonality constraint has been imposed between the continuum functions and the valence atomic orbitals in 47-level calculation. Oscillator strengths and transition probabilities for the fine-structure transitions have been calculated using nonorthogonal orbitals in the multi-configuration Hartree-Fock approach. The present oscillator strengths normally compare very well with a previously available calculation. The collision strength is averaged over a Maxwellian velocity distribution to obtain the effective collision strengths as a function of electron temperature. The effective collision strengths are presented over a wide temperature range (2 x 10(3) to 10(5) K) suitable for modeling of astrophysical plasmas.