Electron EDM Search with Trapped Molecular Ions

A sample of trapped molecular ions offers unique possibilities to search for a permanent electron electric dipole moment (EDM). Specifically, we plan to perform this search using the unpaired electron spins in the $^3\Delta_1$ state of trapped HfF$^+$ molecular ions. The ions will be confined in a linear RF Paul trap, allowing for long electron spin coherence times for increased sensitivity to an electron EDM. Effective internal fields of the molecular ions should exceed $10^{10}$~V/cm, and the molecules are easily polarized in $\sim$ 1V/cm electric fields due to a small $\Omega$ doubling splitting in the $^3\Delta_1$ state. HfF$^+$ molecular ions are created via laser ablation of a Hafnium target in the presence of a He + 1\%SF$_6$ supersonic expansion. The expansion cools the ions rovibrational and translational temperatures to a few Kelvin. We will report current experimental progress.