Nuclear moments of neutron-rich aluminum isotopes

Ground-state magnetic-dipole moments (μ) of ^30-32Al and electric quadrupole moments (Q) of ^31,32Al have been measured with the β-NMR method using spin-polarized radioactive-isotope beams produced in projectile-fragmentation reactions. Beams of ^30-32Al were obtained by using RIKEN projectile-fragment separator RIPS after the fragmentation of ⁴⁰Ar projectiles at an energy of E = 95A MeV on a ⁹³Nb target. The obtained μ_exp[^30-32Al] and values agree well with shell-model calculations within the sd shell using the USD interaction. Also, Q_exp[³¹Al] was found to be small. Thus, we can conclude that these aluminum isotopes are located outside the island of inversion.     

Nuclear moments of the neutron-deficient thallium isotopes

The nuclear moments of the neutron-deficient^187,188Tl isotopes were determined by measuring the hyperfine structure splittings of the λ=535 nm line in neutral thallium. An optical efficiency of 2×10⁻⁴ photons per radioactive ion was achieved using collinear fast beam laser spectroscopy with a large solid angle fiber optical array detector. Most of the moments can be interpreted fairly well in the single particle model.     

Nuclear ground state spins of short-lived strontium isotopes

Nuclear ground state spins of the odd-mass strontium isotopes between A=79 and 97 were determined by measurements of the hyperfine structure in the ionic transition 5s²S_1/2?5p²P_3/2. The spins of⁹³Sr and⁹⁷Sr are revised to I=5/2 and I=1/2, respectively, while assignments for the remaining isotopes are confirmed.     

Nuclear moments and charge radius changes in platinum isotopes

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 Separator) apparatus installed at the ISOCELE facility. Magnetic and quadrupole moments have been deduced from the HFS results. The charge radius changes determined for these odd nuclei from the IS results, added to the σ<r²> values of the even-A nuclei are compared to the results of lattice Hartree-Fock+BCS calculations for asymmetric solutions:¹⁸⁵Pt is confirmed to be prolate shaped whereas^{187, 189, 191}Pt are likely triaxial in their ground states.     

Nuclear moments of neutron deficient iridium isotopes from laser spectroscopy

Laser spectroscopy measurements have been performed on neutron deficient iridium isotopes. The hyperfine structure and isotope shift of the optical Ir I transition 5d⁷6s^{2 4}F_9/2 → 5d⁷6s6p ⁶F_11/2 at 351.5 nm have been studied for the ^182–189Ir, and ^191,193Ir isotopes. The nuclear magnetic and quadrupole moments were obtained from the HFS measurements and the changes of the mean square charge radii from the IS measurements. A large mean square charge radius change between ¹⁸⁷Ir and ¹⁸⁶Ir and between and has been observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Nuclear spins and magnetic moments of some neutron-deficient rubidium isotopes

The nuclear spins and magnetic moments of some neutron-deficient rubidium isotopes have been measured by atomic-beam magnetic resonance techniques at the ISOLDE facility, CERN. The following results have been obtained: ⁷⁷Rb, $\text{I =}\text{3}\text{2}\text{, μ}{}_{\mathrm{I}}\text{= 0.652(7)}\text{n.m.}$; ⁷⁸Rb, I = 0; ^78mRb,I = 4, μ_I = 2.56(3)(rmn.m.); $\text{(su79)}\text{Rb}\text{, I =}\text{5}\text{2}\text{, ifμ}{}_{\mathrm{I}}\text{= 3.364(4)}\text{n.m.}\text{,}\text{and}{}^{\mathrm{<mtext>84</mtext><mtext>m</mtext>}}\text{Rb}\text{, I = 6}$.The data on the The data on the light rubidium isotopes gives evidence for deformed nuclear shapes     

Nuclear moments and change in the charge-radii of neutron deficient lead isotopes

The nuclear moments of¹⁹⁵Pb and the change in the charge radii of^{192,194,195,196}Pb have been determined from the isotope shift and hyperfine structure of the 723 nm line of neutral lead by collinear laser spectroscopy.     

Nuclear moments and charge radii of neutron-rich Rb isotopes by fast-beam laser spectroscopy

A systematic study of nuclear moments and rms charge radii in Rb was made possible by extending high-resolution cw laser spectroscopy into the deep blue. Measurements of optical isotope shifts and hyperfine structure of fission-produced ^89?93Rb are reported.     

Nuclear moments and charge radii of rare-earth isotopes studied by collinear fast-beam laser spectroscopy

The collinear fast-beam laser technique is being used to measure systematically hyperfine structures and isotope shifts of unstable nuclides in the rare-earth region. This brief report gives a general survey of the results obtained for the even-Z elements₆₄Gd,₆₆Dy,₆₈Er and₇₀Yb, with emphasis on the nuclear spins and moments. They allow a rather complete mapping of the single-particle structure and the development of nuclear deformation in the N > 82 region. The spins, magnetic moments and spectroscopic quadrupole moments of^159–169Yb are presented in detail.On leave from Bhabha Atomic Research Centre, Bombay, India.On leave from Institut für Physik, Mainz, Fed. Rep. of Germany.This work has been supported financially by the Deutsche Forschungsgemeinschaft and the Bundesministerium für Forschung und Technologie.     

Nuclear spin of a new isomer in 119Cs and magnetic moment of 120Cs evidence for strongly deformed nuclear shapes of the light cesium isotopes

The nuclear spin, $\text{I =}\text{3}\text{2}$, of a new isomer in ¹¹⁹Cs and the magnetic moment, μ_I = 3.92(5) n.m., of ¹²⁰Cs have been determined in on-line ABMR experiments at the ISOLDE facility, CERN. The experimental data give evidence for strongly deformed nuclear shapes of the light cesium isotopes.     

Nuclear anapole moments

An approximate analytical expression is obtained for the parity violating electromagnetic, so-called anapole, moment of a spherical nucleus. The result iis confirmed by numerical computation in the Woods-Saxon potential for the nuclei ¹³³Cs, ^203,205Tl, ²⁰⁷Pb, ²⁰⁹Bi. The effective coupling constant of the electromagnetic P-odd electron-nucleus interaction constitutes 0.3–0.4 of the Fermi constant.     

Spin-orbit interaction in strongly deformed nuclides

Mass yields observed in asymmetric fission are used to constrain the parameterization of the spin-orbit term of the neutron single particle potential at large deformations.     

Nuclear structure and decay modes of Ra isotopes within an axially deformed relativistic mean field model

We examine the structural properties and half-life decay of Ra isotopes within the axially deformed Relativistic Mean-Field(RMF)theory with NL3 force parameters.We work out the binding energy(BE),RMS radii,two-neutron separation energies(S_(2n)),and some other observables.The results are in good agreement with the finite-range droplet model(FRDM)and experimental results.Considering the possibility of neutron magic number,theα-decay and cluster decay half-lives of Ra isotopes are calculated systematically using the Q-values obtained from the RMF formalism.These decay half-life calculations are carried out by taking three different empirical formulae.The calculated decay half-lives are found to be highly sensitive to the choice of Q-values.Possible shell or sub-shell closures are found at daughter nuclei with N=128 and N=126 when alpha and~8Be,~(12)C,~(18)O respectively are emitted from Ra isotopes.Though the cluster radioactivity is affected by the shell closure of parent and daughter,a long half-life indicates the stability of the parent,and a small parent half-life indicates that the shell stability of the daughter against decay.     

Isobaric analogue states in strontium isotopes

Zeitschrift für Physik A Hadrons and nuclei - Excitation functions for the reactions87Rb(p, n)87Sr and85Rb(p, n)85Sr have been measured in the energy range 2.3–5.6 MeV. Some isobaric...     

Nuclear moments and the change in the mean square charge radius of neutron deficient thallium isotopes

The hyperfine structure, isotope and isomeric shifts in the atomic transition 6p ² P _3/2–7s ² S _1/2, =535 nm have been measured for theI=7 andI=2 states of^{190, 192, 194, 196}Tl; theI=1/2 andI=9/2 states of¹⁹¹Tl and the I=7 isomer of¹⁸⁸Tl. The thallium isotopes were prepared as fast atomic beams at the GSI on-line mass separator following fusion reactions and — in some cases — subsequent-decay. The nuclear dipole moments, electric quadrupole moments and the change in the nuclear mean square charge radius are evaluated. Theuu-isotopes show an isomeric shift which changes sign between¹⁹²Tl and¹⁹⁴Tl.Dedicated to P. Armbruster on the occasion of his 60th birthday     

Quadrupole moments in the cadmium isotopes

Contrary to theoretical predictions and previous experimental results, a new systematic study of the static quadrupole moments Q₂₊ in the even-mass cadmium isotopes using the re-orientation effect shows no evidence of significant variation in Q₂₊ with mass number. For ¹¹⁶Cd, B(E2: 0⁺ → 2⁺) is found to be 20% lower than the previously adopted value.     

Growth of subgrains in strongly deformed polycrystalline nickel

The growth of subgrains is studied in strongly deformed 99·80% pure polycrystalline nickel. The observed zone of the specimen was heated by means of an illuminating electron-beam. It has been verified that the subgrains grow by the migration of their boundaries in steps of the order of 1 . In metals, the subgrains, the nuclei of which are already observed in the deformed material, grow first. Before a perfect subgrain is formed, its nucleus with diffusion subboundaries can always be found. The formation of subgrains by the coalescence of individual slightly misoriented zones is observed in some cases. The growth of subgrains in further stages however, does not, proceed in the above manner.The author is indebted to Dr. M. Rozsíval Dr. Sc., head of the electron microscopy laboratory of the ISSP for help in the work, to Dr. Míek C.Sc. for his interest and discussions on the problem, and to other colleagues of the department of physics of metals of the ISSP for critical comments.