The optical Stark effect in numerous low-J branch features in the Omega = 0(+) <- X-3 Sigma(-)(0) band near 19 040 cm(-1) of nickel oxide, NiO, has been recorded and analyzed. The permanent electric dipole moment, (mu) over bar (el), for the X-3 Sigma(-)(0)(v = 0) and [19.04] Omega = 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] Omega = 0(+) state. (C) 2014 Elsevier BM. All rights reserved.