X rays from foil-excited iodine beams

M--- x-ray spectra from foil-excited iodine beams between 40 and 62 MeV have been studied using a bent-crystal spectrometer. The prompt spectrum is so rich as to defy analysis, but the delayed spectrum exhibits a number of resolved lines. Electric quadrupole 4s→3d transitions are observed from metastable systems in the Ni i, Cu i, and Zn i isoelectronic sequences. Electric dipole 4p→3d transitions from states in these isoelectronic sequences also appear downstream. Transition energies and quadrupole lifetimes have been measured and are compared with the results of both relativistic and nonrelativistic calculations.