Accurate Electronic and Vibrational Structure Calculations of Metal-Containing Small Molecules of Importance to Precision Measurement and Laser Cooling

The proposed research consists of computational studies to describe the complex motions of electrons and nuclei in small metal-containing molecules that play important roles in searching for new physics beyond the Standard Model and in the emerging quantum information sciences. The proposed work on computational techniques is focused on the development of new algorithms and computer programs to elucidate the roles of subtle coupling between electronic states in laser cooling of molecules to ultracold temperature. The proposed molecular applications in close collaboration with experimental groups aim to provide insights into molecules relevant to cutting-edge research in quantum sciences and in searches for new physics. The method-development work proposed here is focused on relativistic coupled-cluster theory to enhance the treatment of nonadiabatic effects of importance to laser cooling of molecules containing heavy atoms and to improve the ability to calculate effective electric fields of importance to precision measurement of the electron’s electric dipole moment (eEDM). The proposed application work consists of a thorough investigation of the intensity-borrowing mechanisms in laser-coolable linear polyatomic molecules and predictions of properties for metal-containing small molecules including RaOH, ThF+, and YbOH, in close collaboration with experimental groups working on laser cooling and precision spectroscopy of these molecules. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.