Theoretical calculations of energy levels and transitions for neutral lutetium

Abstract Multiconfiguration Dirac-Hartree–Fock (MCDHF) and relativistic configuration interaction (RCI) methods are employed for theoretical calculations of energy levels, wavelengths, line strengths, logarithmic weighted oscillator strengths and transition probabilities in 5d6s 2 -5d6s6p, 5d6s 2 -6s 2 6p, 5d6s 2 -6s 2 6f, 6s 2 6p-6s6p 2 and 5d6s6p-6s6p 2 transitions of neutral lutetium. The average accuracies of the energy levels and transition wavelengths compared with the NIST database are 3.56% and 2.58%, respectively. The differences for most energy levels are below 5% and transition wavelengths are below 6.84%. The uncertainties of the transitions were classified based on line strength through integrated quantitative and qualitative assessments, with 55% of the transitions assigned to accuracy classes higher than class E. The present calculated values show a certain degree of consistency with the existing experimental and theoretical results, and the new theoretical values are expected to be helpful for research on lutetium atoms.