Study of the lead monofluoride molecule in preparation of a measurement of the electric dipole moment of the electron

Abstract

The electric dipole moment of the electron (e-EDM) has important consequences in fundamental theories of matter. Since it was first suggested by Purcell and Ramsey in 1950, it has been pursued in large particle accelerators and table-top atomic beam experiments. The most stringent limit on the upper bound of the e-EDM (|p| < 1.6 × 10^-27 e · cm) was placed by a series of Thallium atomic beam experiments of Commins and coworkers between 1990 and 2002.

As early as 1975 Sandars realized that certain heavy polar diatomic molecules offer orders of magnitude greater intrinsic sensitivity to the e-EDM than do atoms. However, molecules introduce many new challenges over atoms, including difficulties in production, state dilution, and detection. For this reason, molecular e-EDM measurements are only now beginning to compete with atomic measurements. This dissertation addresses the difficulty of detection of the e-EDM-sensitive lead monofluoride molecule and presents the results of studies that characterize the spectroscopy of the molecule. In all, over 30 spectroscopic parameters have been measured, covering electronic, fine, and hyperfine interactions. These measurements are essential for optimizing detection, analyzing systematic errors and interference from other states, and designing a Ramsey technique for, ultimately, the measurement of the e-EDM.