Detailed spectroscopy of the a(1) [3Σ+] state of PbO

An experimental search for the electron electric-dipole moment using the a(1)[ 3 Σ + ] state of PbO is currently underway and promises to yield high precision. Several experimental parameters are required as input to theoretical determinations of the sensitivity of the proposed experiment. We use molecular-beam spectroscopy to determine the hyperfine constant, molecular dipole moment, and Lande g factor of the a(1) state, and the electronic isotope shifts of the X-a transition.