  The multi-configuration Dirac-Hartree-Fock method was employed to calculate
the total and excitation energies, oscillator strengths and hyperfine structure
constants for low-lying levels of Sm I. In the first-order perturbation
approximation, we systematically analyzed correlation effects from each
electrons and electron pairs. It was found that the core correlations are of
importance for physical quantities concerned. Based on the analysis, the
important configuration state wave functions were selected to constitute atomic
state wave functions. By using this computational model, our excitation
energies, oscillator strengths, and hyperfine structure constants are in better
agreement with experimental values than earlier theoretical works.
