Sensitivity coefficients to \(\alpha\)-variation for astrophysically relevant transitions in Ni II

Abstract

We calculated the dependence of the transition frequencies on the fine-structure constant \(\alpha\) (\(q\)-factors) for Ni~II. Nickel is one of the few elements with high sensitivity to \(\alpha\)-variation, whose lines are observed at high redshifts. This makes it a sensitive probe for \(\alpha\)-variation on the cosmological timescale. The electronic structure of Ni II ion was treated within the configuration interaction (CI) method using Dirac-Coulomb Hamiltonian.