High-resolution laser photoionization spectroscopy of radioactive europium isotopes

A study is made of the autoionization spectrum for transitions of the Eu atom from excited states. The most efficient schemes are found for the three-step laser photoionization of Eu atoms. The data are used for measurement of the isotope shifts in the optical spectrum of the radioactive isotopes of Eu at the laser-nuclear complex at the Leningrad Institute of Nuclear Physics and the Institute of Spectroscopy. On the basis of the measured isotope shifts we have determined for the first time the changes in the mean-square distribution of nuclear charge for the radioactive isotopes /sup 150hyphen145/Eu. The prospects for improving the sensitivity of the method are discussed.