Transitions from the 3p63d ground state of potassium-like vanadium

Abstract

The three lowest ions in the K-like sequence, Ca II, Sc III and Ti IV have excited states 3p53d2 and 3p53d 4s which lie above the 3p6 ionization threshold. These excited (resonance or autoionizing) states increase greatly the cross sections for electron and photon ionization of the ground state of the ion. As the charge of the ion increases the number of resonance states of the form 3p53d2 or 3p53d 4s which lie above the 3p6 ionization threshold decreases. At present there is no experimental evidence for the existence of these resonances in V V, the next ion in the K-like sequence. Theoretical calculations (Tiwary et al 1983 J. Phys. B: At. Mol. Phys. 16 2457) suggest that there is a [3d 1P4s] 2P resonance in V V at an excitation energy of 2.81 au above the 3p63d ground state. This paper presents an ab initio calculation of the transition energies and A-values between individual J levels of the ground 3p63d state and the J levels of the 3p6np, 3p6nf and the 3p53d2 and 3p53d 4s excited states of V V. These calculations indicate that there is a resonance multiplet [3d 1P 4s] 2P at an excitation energy of 2.73 au which is 0.33 au (9.0 eV) above the 3p 6 ionization threshold.