Relativistic configuration-interaction calculations using hydrogenlike or Dirac-Fock spin orbitals of the transition from the ground state to some $n{p}_{1/2}$, $n{p}_{3/2}$ low-lying excited states for the alkali metals are presented. In these calculations each virtual spin orbital corresponds to a unique noninteger atomic number determined iteratively using the virtual-particle model. The virtual-particle model based on “condensed-space” idea is here adopted to many electron systems consisting of a single valence electron and the core. The transition energy and the oscillator strength values were computed for sodium, potassium, rubidium, cesium, and francium. Both hydrogenlike and Dirac-Fock basis functions have been used in the computations for comparison.

• Received 15 September 2015

DOI:https://doi.org/10.1103/PhysRevA.92.062505