The permanent electric dipole moment of thorium sulfide, ThS

Numerous rotational lines of the {18.26} 1-X-1 Sigma(+) band system of thorium sulfide, ThS, were recorded near 547.6 nm at a resolution of approximately 30 MHz. Measurements were made under field-free conditions, and in the presence of a static electric field. The field-free spectrum was analyzed to produce rotational and Lambda-doubling parameters. The Stark shifts induced by the electric field were analyzed to determine permanent electric dipole moments, (mu) over arrow(el), of 4.58(10) D and 6.72(5) D for the X-1 Sigma(+) ( v = 0) and {18.26} 1 states, respectively. The results are compared with the predictions of previous and new electronic structure calculations for ThS, and the properties of isovalent ThO. (C) 2014 AIP Publishing LLC.