Quadrupole Coupling in the Hyperfine Structure of the Spectra of Ta I and Os I

Abstract

The shielding correction Δ defined by Q=(1+Δ)Q′ (Q=true quadrupole moment; Q′=apparent quadrupole moment obtained by spectroscopic means neglecting the shielding effect) was investigated in the cases of the state 5d⁴6s of Ta I and 5d⁶6s6p of Os¹⁸⁹ I. In these cases the correction Δ for the group 5d⁴6s or 5d⁶6s was found to be of the order of 9±5; namely the shielding effect predominates over the antishielding effect. It is highly probable that Δ is around zero in the state 5d⁶ of Os I. The quadrupole moment of Os¹⁸⁹ is 0.8±0.2 barn. The hyperfine structure due to Os¹⁸⁷ was also studied, and μ(187)=+0.0656±0.0006 nm, was obtained.