Oscillator strengths and electron collisional excitation cross sections for atomic oxygen.

Abstract

Absorption oscillator strengths for dipole-allowed transitions among the 2${p}^{4}$ $^{3}P$, 3s $^{5}$,3S\ifmmode^\circ\else\textdegree\fi{}, 3p $^{5}$,3P, 4s $^{5}$,3S\ifmmode^\circ\else\textdegree\fi{}, 3d $^{5}$,3D\ifmmode^\circ\else\textdegree\fi{}, 4p $^{5}$,3P, and 3s' $^{3}\mathrm{\ifmmode^\circ\else\textdegree\fi{}}$ states of O i are calculated in length and velocity formulations using extensive configuration-interaction wave functions. We also include these 12 states in our close-coupling calculations of the inelastic cross sections for O i. Cross sections for excitation of the 3s $^{5}\mathrm{\ifmmode^\circ\else\textdegree\fi{}}$, 3p $^{5}P$, 4s $^{3}S$\ifmmode^\circ\else\textdegree\fi{}, 4p $^{3}\mathrm{P}$, 3d $^{3}D$\ifmmode^\circ\else\textdegree\fi{}, and 3s' $^{3}D$\ifmmode^\circ\else\textdegree\fi{} states by electron impact are presented in the energy region from 13.87 to 100 eV and these are compared, where available, with other calculations and experiments. The present results are in good agreement with the recent experiments at energies 13.87, 20, and 30 eV for the $^{3}\mathrm{p}$ $^{5}\mathrm{P}$ transition and at energies 13.87 and 16.5 eV for the $^{3}\mathrm{s}$ $^{5}\mathrm{\ifmmode^\circ\else\textdegree\fi{}}$ transition. However, the present cross sections for the $^{3}\mathrm{s}$ $^{5}\mathrm{\ifmmode^\circ\else\textdegree\fi{}}$ transition at 20 and 30 eV are large by a factor of 2 compared to experiment. There are discrepancies between theory and experiment in magnitude for the dipole-allowed $^{3}\mathrm{d}$ $^{3}\mathrm{\ifmmode^\circ\else\textdegree\fi{}}$ and $^{3}\mathcal{'}$ $^{3}\mathrm{\ifmmode^\circ\else\textdegree\fi{}}$ transitions.