The measurement of E2 and E4 moments using exotic atoms

Recent developments in the determination of quadrupole and hexadecapole moments of nuclear charge distributions using the exotic atom technique are discussed. As an indication of the sensitivity of muonic data to higher charge moments, the discussion is concentrated on recent work in highly deformed nuclei. Using the hyperfine structure (h.f.s.) of the muonic 3d state it is not difficult to obtain 1% accuracy for the static E2 moment of the ground state. Typically 40% accuracy can be ascribed to E4 moment determinations. The 2p h.f.s. can be used to determine the static moments of excited states as well as the dynamic moments (or BE2's) connecting these states with the ground state. Combining this information with radial charge parameter information from the absolute transition energies of the 2p → 1s(K) and 3d → 2p(L) transitions allows one to study the distribution of the E2 density. (Auth.)