Proton excitation of fine-structure transitions in Fe XIV

Abstract

The interaction potentials of the quasimolecular $\ensuremath{\Sigma}$ and $\ensuremath{\Pi}$ states formed by the approach of a proton and the positive ion ${\mathrm{Fe}}^{13+}$ are calculated in an approximation which reproduces the long-range quadrupole and polarization terms and which accounts properly for short-range penetration effects. The interaction potentials are used in quantal calculations of the cross sections for proton-impact excitation of fine-structure transitions of ${\mathrm{Fe}}^{13+}$. Solutions of the close-coupled scattering equations are obtained and the resulting cross sections are compared with those given by the Coulomb-Born and elastic approximations. The sensitivity of the cross sections to features of the interaction potentials is explored. The Coulomb-Born and elastic approximations do not always reflect faithfully the physical characteristics of the potentials.