Configuration-interaction calculations on the 3s23pn configuration of neutral phosphorus and two of its ions

Abstract

We perform valence, core-core, and core-valence nonrelativistic configuration-interaction (CI) calculations on the states belonging to the $3{s}^{2}3{p}^{n}$ configuration with $n=2$, 3, and 4, for ${\mathrm{P}}^{+}(^{3}P,^{1}D, ^{1}S$), $\mathrm{P}{(}^{4}{S}^{\ensuremath{\circ}},^{2}D^{\ensuremath{\circ}}, ^{2}P^{\ensuremath{\circ}}$), and ${\mathrm{P}}^{\ensuremath{-}}(^{3}P,^{1}D, ^{1}S$) species, respectively. Excitation energies, ionization potential, and electron affinities related to these states were calculated using orbital basis sets up to $\ensuremath{\ell}=12$ and corrected with relativistic contributions. We also carry out relativistic CI calculations for the fine structure splitting of the sublevels ${}^{3}{P}_{0,1,2}$ and ${}^{3}{P}_{2,1,0}$ in ${\mathrm{P}}^{+}$ and ${\mathrm{P}}^{\ensuremath{-}}$, respectively, and both ${}^{2}{D}_{3/2,5/2}^{\ensuremath{\circ}}$ and ${}^{2}{P}_{1/2,3/2}^{\ensuremath{\circ}}$ in P, using orbital basis sets up to $\ensuremath{\ell}=3$. Systematic studies on the convergence of both nonrelativistic and relativistic CI calculations for each electronic state show the energy contributions corresponding to each CI excitation level. Our results for the excitation energies, ionization potential, and electron affinity of the ${(3{s}^{2}3{p}^{3})}^{4}{S}^{\ensuremath{\circ}}$ ground state, as well as fine structure splittings, are in very good agreement with the experiment and give reliability to the predicted electron affinities of the ${(3{s}^{2}3{p}^{3})}^{2}{D}^{\ensuremath{\circ}}$ and $^{2}P^{\ensuremath{\circ}}$ excited states of 1135(1) meV and 1040(1) meV, respectively.