J. Pinard

Hyperfine structure and isotope shift of the D2 line of 118–145Cs and some of their isomers

Abstract High-resolution laser spectroscopy has been performed on 118–145 Cs and 119m, 121m, 122m, 130m, 134m, 135m, 136m, 138m, Cs.The Cs nuclei have been produced either by spallation of La or by fission of U by the 600 MeV proton beam, from the SC at CERN. The hyperfine structures, spins, and isotope shifts have been measured. The charge radii changes deduced from the isotope shifts exhibit shell effects at N = 82, isomeric staggering for N = 64,66,67 and a strong odd-even staggering for all isotopes with N

Hyperfine structures and isotope shifts of 207–213,220–228Fr; Possible evidence of octupolar deformation

Abstract Hyperfine structures and isotope shifts of 207–213,220–228 Fr have been measured by high-resolution laser spectroscopy. Nuclear moments and changes in the mean-square charge radii are deduced. They are compared with analogous data for radium and discussed in terms of the octupole deformation mode.

Isotope shifts, spins and hyperfine structures of 118,146Cs and of some francium isotopes

Abstract High-resolution laser spectroscopy using thermal atomic beams has been performed on-line with the ISOLDE facility at CERN. It allowed the measurement of the spins, isotope shifts and hyperfine structures of the D2 line of 118,146Cs, and that of the hyperfine factors of the first P 1 2 level of 133,135,137,139,141,143Cs and 210,212,213,221Fr. Previous data concerning 207–213,220–228Fr have also been reanalysed. All results are discussed in terms of deformations with special attention to the possible occurrence of octupole deformations.

Shape transition in neutron deficient Pt isotopes

Abstract Isotope shift (IS) and hyperfine structure (HFS) measurements have been performed for 185,187,189,191,195 Pt using the PILIS (Post ISOCELE Laser Isobar Separation) apparatus installed at the ISOCELE facility. Magnetic and quadrupole moments have been deduced from the HFS results. The change radius changes determined for these odd nuclei from the IS results, added to the δ r 2 > values of the even- A nuclei, are compared to the results of lattice Hartee-Fock+BCS calculations for asymmetric solutions. 185 Pt is confirmed to be prolate shaped whereas 187,189,191 Pt are likely triaxial in their ground states.

Laser spectroscopy of laser-desorbed gold isotopes

Abstract Changes in mean-square charge radius δ〈r2〉, and magnetic dipole moments μ1 have been measured for a series of neutron-deficient gold isotopes between A = 186 and 196, and for neutronrich 198,199Au, using the PILIS system on-line with the ISOCELE mass separator. These measurements confirm the existence of the shape transition between A = 186 and 187. The measured μ1 values have been compared with calculations using Nilsson, and symmetric-rotor-plus-quasiparticle models. The results are consistent with the interpretation that 186Au is prolate, and that the heavier isotopes have oblate, or possibly triaxial deformation.

COMPLIS experiments: COllaboration for spectroscopy Measurements using a Pulsed Laser Ion Source

Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments μ, spectroscopic quadrupole moments Qs and changes of the nuclear mean square charge radius δ〈rc2〉along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented.

Rydberg atoms in parallel magnetic and electric fields. I. Experimental studies of the odd diamagnetic multiplet of lithium: n mixing and core effects

A quasihydrogenic complete diamagnetic manifold is investigated experimentally. The spectra are obtained in a uniform magnetic field by exciting in a one-step process, using polarised laser light, the lithium atoms of an atomic beam. The whole structure of the M=0 odd diamagnetic multiplet has been recorded for the first time. This experiment provides a confirmation for the existence of the two classes of states predicted for the diamagnetic Hamiltonian of atomic hydrogen in the weak-field limit. The fundamental features of diamagnetism still subsist for such high field strengths so that the diamagnetic interaction cannot be regarded as a perturbation with respect to the Coulomb problem. The intermanifold coupling and the influence of effects due to the ionic core in the lithium atom are evaluated quantitatively.

Accurate wavenumbers of the first resonance doublet of francium atoms and relativistic contribution to isotope shifts in the resonance doublets of francium and caesium atoms

The results of a new experiment using high-resolution Doppler-free laser spectroscopy are reported. Firstly, the wavenumbers of the D1 and D2 lines of Fr atoms have been accurately measured: sigma (D1)-12237.409 (2) cm-1 and sigma (D2)=13923.998 (2) cm-1. Secondly, the isotope shifts of the D1 and D2 lines have been compared for Fr and Cs atoms. The contribution of the p1/2 electron to the volume shift has been measured relative to that of the s1/2 electron as 4.75(25)*10-2 for Fr and 1.4(3)*10-2 for Cs. They are discussed in terms of semi-empirical calculations as well as relativistic Dirac-Fock ones.

Nuclear moments of neutron deficient iridium isotopes from laser spectroscopy

AbstractLaser spectroscopy measurements have been performed on neutron deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d76s24F9/2 → 5d76s6p 6F11/2 at 351.5 nm have been studied for the 182–189Ir,