Studies of barium monofluoride molecules embedded in a cryogenic neon solid: Steps towards a measurement of the electron electric dipole moment*

Improved measurements of the electron electric dipole moment (eEDM) will strongly constrain the parameter space of new physics theories. Over the last decade, polar molecules have become established as the most promising systems for eEDM searches, due to the large internal electric fields experienced by an eEDM in these molecules. We report here on large samples of barium monofluoride (BaF) molecules embedded into a cryogenic (6 K) solid neon matrix. These samples have been extensively studied, including studies of laser-induced fluorescence, radiative and nonradiative lifetimes, optical pumping, rf transitions between hyperfine states, lineshapes, and Zeeman structure. Experiments using time sequences of laser and rf pulses allow for more detailed studies. This work sets up some of the crucial steps needed for a full time sequence [1] that would allow for a precision measurement of the electron electric dipole moment using these matrix-isolated polar molecules. 

[1] A. C. Vutha, M. Horbatsch and E. A. Hessels, Phys. Rev. A 98, 032513 (2018).