Communication: The permanent electric dipole moment of thorium monoxide, ThO

The optical Stark spectrum of the E (0 + ) − X 1 Σ + (1,0) band of thorium monoxide, ThO, was recorded and analyzed to determine the permanent electric dipole moments, μ , for the E (0 + ) ( v = 1) and X 1 Σ + ( v = 0) states. Values of 2.782 ± 0.012 D ( X ) and 3.534 ± 0.010 D ( E ) were obtained. The uncertainties are 2σ statistical error. The systematic errors are estimated to be less than 1%. The experimental results are used to access the quality of electronic structure calculations of the properties of the X 1 Σ + ( v = 0) state.