Hyperfine Effects in Muonic Bi and Pb

We have investigated the K and L transitions in the muonic spectra of Bi²⁰⁹ and of the separated isotopes Pb²⁰⁶, Pb²⁰⁷, and Pb²⁰⁸, using a Ge(Li) spectrometer. Our isotope shifts in Pb, in excellent agreement with the optical data, are half those predicted by the A1/3 law. The agreement between our shifts and the optical shifts strongly suggests the absence of nuclear polarization by the muon. We have studied the $M1$ and $E2$ hyperfine (hf) interactions in Bi²⁰⁹. The $M1$ results, although not sensitive enough to distinguish models of nuclear magnetization distributions, rule out a point magnetic dipole. The $E2$ constants, when used in conjunction with the measured isotone shift between Bi²⁰⁹ and Pb²⁰⁸, suggest a quadrupole distribution produced by an h9/2 proton and a slightly ({~}1%) deformed Pb²⁰⁸ core. We have examined the effects of $E3$ mixing of Bi²⁰⁹ nuclear levels on the K and L intensity ratios and on the interpretation of the hf constants.