Measurement of the isotope shift and hyperfine structure splitting Xe II by collinear fast-ion-beam laser spectroscopy

The isotope shifts and hyperfine structure splittings of nine stable xenon isotopes in the mass range from 124 to 136 were measured using the electronic transition 5d4D72-6p4P520 in the Xe II spectrum. The method of collinear fast-ion--beam laser spectroscopy was utilized to achieve Doppler-free resolution and a high sensitivity. An ion-beam apparatus consisting of an Einzel lens, a switch magnet, and two electrostatic quadrupole triplets was designed to transport the ions from an on-line ion source through the TRISTAN isotope separator to the interaction region where, at resonance, the fluorescence signal was observed. A line-shape analysis, based on an asymmetrical exponential function, was developed to interpret the recorded data. Changes in the mean square charge radii δ(r2)/sup AA'/ for the chain of stable xenon isotopes were extracted from the measured isotope shifts. The hyperfine-structure constants A and B, the nuclear magnetic dipole moment μ/sub l/, and the electric quadrupole moment Q were evaluated from the splittings. The effect of the nuclear deformation below the magic number 82 is discussed in the two-parameter liquid drop model and the three-parameter droplet model. A comparison of the δ(r2)/sup AA'/ of Xe with those of the neighboring elements of Cs and Ba is made