Stark-modulation spectroscopy of the B(1)$[^3Π]$ state of PbO

We report detailed spectroscopic measurements of the X(0)$[^3Σ^+]$(v=0) to B(1)$[^3Π]$ (v=5) transition in PbO. Using a Stark-modulated laser absorption technique, we have measured the hyperfine constant of $^{207}$PbO in the B(1) state, as well as B(1)(v=5) rotational constant, X-B isotope shifts, etc. The hyperfine structure of the B(1) state is of interest as a benchmark for calculations of PbO electronic structure, related to experiments to search for the electric dipole moment of the electron.