Experimental radiative lifetimes for highly excited states and calculated oscillator strengths for lines of astrophysical interest in singly ionized cobalt (Co II)

TL;DR

This study combines new experimental radiative lifetime measurements with theoretical calculations to provide accurate oscillator strengths for Co II lines, aiding astrophysical research.

Contribution

It reports nineteen new radiative lifetimes for Co+ and calculates oscillator strengths for over 5000 transitions using a relativistic Hartree-Fock model.

Findings

Good agreement between experimental and theoretical lifetimes.

New radiative lifetimes for high-lying Co+ states.

Reliable oscillator strengths for Co II transitions from 114 to 8744 nm.

Abstract

This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions of astrophysical interest in singly ionized cobalt. More precisely, nineteen radiative lifetimes in Co+ have been measured with the time-resolved laser-induced fluorescence technique using one- and two-step excitations. Out of these, seven belonging to the high lying 3d$^7$($^4$F)4d configuration in the energy range 90697 - 93738 cm$^{-1}$ are new, and the other twelve from th3d$^7$($^4$F)F)4p configuration with energies between 45972 and 49328 cm$^{-1}$1 are compared with previous measurements. In addition, a relativistic Hartree-Fock model including core-polarization effects has been employed to compute transition rates. Supported by the good agreement between theory and experiment for the lifetimes, new reliable transition probabilities and oscillator strengths have been deduced for 5080 Co II transitions in the spectral range 114 - 8744 nm.