The permanent electric dipole moment of nickel oxide, NiO

The optical Stark effect in numerous low-J branch features in the Ω = 0 + ← X 3 Σ 0 - band near 19 040 cm−1 of nickel oxide, NiO, has been recorded and analyzed. The permanent electric dipole moment, μ → el , for the X 3 Σ 0 - ( v = 0 ) and [19.04] Ω = 0 + states were determined to be 4.43 ± 0.04 D and 1.85 ± 0.16 D, respectively. The measured dipole moments of NiO are compared to those from theoretical predictions and the trend across the 3d-metal monoxide series discussed. The field-free spectrum was analyzed to produce an improved set of fine structure parameters for the [19.04] Ω = 0 + state.