Transition energy and dipole oscillator strength for 1s²2p-1s²nd of Cr²¹⁺ ion

The transition energies, wavelengths and dipole oscillator strengths of 1s²2p-1s²nd (3 ≤ n ≤ 9) for Cr²¹⁺ ion are calculated. The fine structure splittings of 1s²nd (n ≤ 9) states for this ion are also calculated. In calculating energy, we have estimated the higher-order relativistic contribution under a hydrogenic approximation. The quantum defect of Rydberg series 1s²nd is determined according to the quantum defect theory. The results obtained in this paper excellently agree with the experimental data available in the literature. Combining the quantum defect theory with the discrete oscillator strengths, the discrete oscillator strengths for the transitions from initial state 1s²2p to highly excited 1s²nd states (n ≥ 10) and the oscillator strength density corresponding to the bound—free transitions are obtained.