Prospects for an electron electric-dipole moment search in metastable ThO and ThF+

The observation of an electron electric-dipole moment (EEDM) would have major ramifications for the standard model of physics. Polar molecules offer a near-ideal laboratory for such searches due to the large effective electric field (F-eff), on order of tens of GV/cm that can be easily oriented in the laboratory frame. We present an improved method for simply and accurately determining F-eff, in a heavy polar molecule, allowing for a quick determination of candidates for an EEDM experiment. We apply this method to ThO and ThF+, both of which possess metastable (3)Delta electronic states. The values of F-eff in ThO and ThF+ are estimated to be 104 GV/cm and 90 GV/cm, respectively, making them two of the best known candidates for the EEDM search.