Abstract.
Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d 76s 24 F 9/2 → 5d 76s6p 6 F 11/2 at 351.5nm were measured for 182-189Ir, 186Irm and the stable 191, 193Ir. The nuclear magnetic moments μI and the spectroscopic quadrupole moments Qs were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of μI was experimentally determined for the first time for the masses 182≤A≤189 and the isomeric state 186Irm. The spectroscopic quadrupole moments of 182Ir and 183Ir were measured also for the first time. A large mean square charge radius change between 187Ir and 186Irg and between 186Irm and 186Irg was observed corresponding to a sudden increase in deformation: from β2 ≃ + 0.16 for the heavier group A = 193, 191, 189, 187 and 186m to β2≥ + 0.2 for the lighter group A = 186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the π3/2+[402] orbital for the heavier group and with the π1/2-[541] orbital stemming from the 1h 9/2 spherical subshell for the lighter group. That last state seems to affect strongly the observed values of the nuclear moments.
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References
J. Bonn, Phys. Lett. B 38, 308 (1972).
G. Ulm, Z. Phys. A 325, 247 (1986).
K. Wallmeroth, Phys. Rev. Lett. 58, 1516 (1987)
G. Seewald, Phys. Rev. Lett. 77, 5016 (1996).
C.R. Hammond, Handbook of Chemistry and Physics (CRC Press, Boca Raton, Florida, 1984-1985) p. B5.
U. Krönert, Nucl. Instrum. Methods A 300, 522 (1991).
G. Savard, Nucl. Phys. A 512, 241 (1990).
H.T. Duong, Phys. Lett. B 217, 401 (1989).
Th. Hilberath, Z. Phys. A 342, 1 (1992).
J.K.P. Lee, Nucl. Instrum. Methods B 34, 252 (1988).
F. Le Blanc, Phys. Rev. Lett. 79, 2213 (1997).
F. Le Blanc, Phys. Rev. C 60, 054310 (1999).
S. Büttgenbach, Z. Phys. A 286, 333 (1978).
S. Büttgenbach, Hyperfine Structure in 4d- and 5d-Shell Atoms (Springer-Verlag, Berlin, Heidelberg, New York, 1982) p. 59.
J.-F. Wyart, private communication (1998).
J.E Crawford, Proceedings of the Sixth International Symposium on Resonant Ionization Spectroscopy and Its Applications, Santa Fe, New Mexico, USA, May 24-29, 1992 (Institute of Physics, Williston, USA, 1992).
F. Le Blanc, Hyperfine Interact. 127, 71 (2000).
J. Sauvage, Hyperfine Interact. 129, 303 (2000) and references therein.
J. Lettry, Nucl. Instrum. Methods B 126, 170 (1997).
P. Kilcher, Nucl. Instrum. Methods A 274, 485 (1989).
I. Brissaud, Nucl. Instrum. Methods B 45, 636 (1990).
D. Verney, Thesis, Université Joseph Fourier-Grenoble I, IPNO-T-01-01 (2000).
W.C. Wiley, I.H. McLaren, Rev. Sci. Instrum. 26, 1150 (1955).
J. Pinard, S. Liberman, Opt. Commun. 20, 344 (1977).
S. Liberman, Rev. Cethedec, NS 83-2 (1983).
G. Savard, Thesis, McGill University (1988).
J. Pinard, Proceedings of the 3rd International Workshop on Hyperfine Structure and Nuclear Moments of Exotic Nuclei by Laser Spectroscopy, Poznan, Poland, February 3-5, 1997 (Joint Institute for Nuclear Research, Dubna, 1998).
P. Kilcher, Nucl. Instrum. Methods B 70, 537 (1992).
F. Le Blanc, Nucl. Instrum. Methods B 72, 111 (1992).
J. Obarheide, Meas. Sci. Technol. 8, 351 (1997).
K.H. Bürger, Phys. Lett. B 140, 17 (1984).
P. Raghavan, At. Data Nucl. Data Tables 42, 189 (1989).
R. Eder, Phys. Rev. C 32, 582 (1985).
R. Eder, Hyperfine Interact. 59, 83 (1990).
S. Ohya, J. Phys. G 14, 365 (1988).
M.G. Booth, Hyperfine Interact. 75, 307 (1992).
A. Narath, Phys. Rev. 165, 506 (1968).
P.A. Moskowitz, M. Lombardi, Phys. Lett. B 46, 513 (1973).
Y. Tanaka, Phys. Rev. C 29, 1830 (1984).
E. Hagn, Phys. Lett. B 104, 365 (1981).
A.L. Allsop, Hyperfine Interact. 12, 289 (1982).
K. Murakawa, T. Kamei, Phys. Rev. 110, 393 (1958).
R.M. Sternheimer, Phys. Rev. 164, 10 (1967).
Y. Tanaka, Phys. Rev. Lett. 51, 1633 (1983).
K. Heilig, A. Steudel, At. Data Nucl. Data Tables 14, 613 (1974).
Th.A.M. Van Kleef, Physica 23, 843 (1957).
G. Torbhom, Phys. Rev. A 31, 2038 (1985).
E.C. Seltzer, Phys. Rev. 188, 1916 (1969).
J.P. Desclaux, Comput. Phys. Commun. 9, 31 (1975).
K. Wallmeroth, Nucl. Phys. A 493, 224 (1989).
S.A. Ahmad, Nucl. Phs. A 483, 244 (1988).
W.D. Myers, W.J. Swiatecki, Ann. Phys. (N.Y.) 55, 395 (1969).
W.D. Myers, K.-H. Schmidt, Nucl. Phys. A 410, 61 (1983).
P. Möller, At. Data Nucl. Data Tables 59, 185 (1995).
H. Flocard, Nucl. Phys. A 203, 433 (1973).
M. Meyer, Nucl. Phys. A 316, 93 (1979).
J. Sauvage, Nucl. Phys. A 370, 231 (1981).
J. Libert, Phys. Rev. C 25, 586 (1982).
M.-G. Porquet, Nucl. Phys. A 451, 365 (1986).
L. Bennour, Nucl. Phys. A 465, 35 (1987)
C. Bourgeois, Nucl. Phys. A 386, 308 (1982)
J. Sauvage, Nucl. Phys. A 592, 221 (1995).
M. Beiner, Nucl. Phys. A 238, 29 (1975).
R.B. Firestone, Table of isotopes (John Wiley & Sons, New York, 1998).
C. Ekström, Phys. Scr. 14, 199 (1976).
I.-L. Lamm, Nucl. Phys. A 125, 504 (1969).
O. Nathan, S.G. Nilsson, Alpha-, beta- and gamma-ray spectroscopy, edited by K. Siegbahn (North-Holland Publ. Co., Amsterdam, 1965) p. 653.
A.J. Kreiner, Nucl. Phys. A 432, 451 (1985).
T. Duguet, Phys. Rev. C 65, 014310 (2002).
J.P. Delaroche, Phys. Rev. C 50, 2332 (1994).
I. Deloncle, Thesis, Université Paris VI, unpublished
M. Girod, J. Libert, private communication.
J. Dechargé, D. Gogny, Phys. Rev. C 21, 1568 (1980)
A. Zerrouki, Thesis, Université Paris Sud-XI (1979) unpublished.
J. Meyer ter Vehn, Phys. Lett. B 55, 273 (1975)
E. van Walle, Hyperfine Interact. 22, 507 (1985).
K.E.G. Löbner, Nucl. Data Tables A 7, 495 (1970).
R.H. Price, Nucl. Phys. A 176, 338 (1971)
R. Piepenbring, H. Nopre, Nucl. Phys. A 133, 113 (1969).
R. Eder, Z. Phys. A 323, 185 (1986).
S. André, Nucl. Phys. A 325, 445 (1979).
A.J. Kreiner, Nucl. Phys. A 425, 387 (1985).
J. Sauvage, Proceedings of the International Conference on Nuclear Structure and Related Topics, Dubna, Russia, 2000, Nucl. Phys. Russ. Acad. Sci. 64, 1210 (2001).
M. Sodan, Nucl. Phys. A 237, 333 (1975).
H. Rubinsztein, M. Gustaffson, Phys. Lett. B 58, 283 (1975).
K.J. Hofstetter, Phys. Rev. C 8, 2442 (1973).
E. Hagn, E. Zech, Z. Phys. A 297, 329 (1980) and references therein.
A.J. Kreiner, Phys. Rev. C 29, 1572 (1984).
G.T. Emery, Nucl. Phys. A 211, 189 (1973).
P.T. Prokofiev, Bull. Acad. Sci. USSR, Phys. Ser. 38, 104 (1974).
A.J. Kreiner, Phys. Lett. B 279, 233 (1992).
M.A. Cardona, Phys. Rev. C 55, 144 (1997).
A. Ben Braham, Nucl. Phys. A 533, 113 (1991).
R. Eder, Hyperfine Interact. 59, 83 (1990).
R. Hochel, Nucl. Phys. A 211, 165 (1973).
M.-G. Porquet, Nucl. Phys. A 499, 495 (1989).
A. Ben Braham, Nucl. Phys. A 482, 553 (1988).
A.J Kreiner, Phys. Rev. C 34, 1150 (1986).
A.J. Kreiner, Nucl. Phys. A 282, 243 (1977).
A. Bohr, B.R. Mottelson, Mat.-Fys. Medd. K. Dan. Vidensk. Selsk. 27, no 16 (1953).
S.G. Nilsson, I. Ragnarsson, Shapes and Shell in Nuclear Structure (Cambridge University Press, Cambridge, 1995) pp. 102-108.
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Verney, D., Cabaret, L., Crawford, J.E. et al. Deformation change in light iridium nuclei from laser spectroscopy. Eur. Phys. J. A 30, 489–518 (2006). https://doi.org/10.1140/epja/i2006-10140-7
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DOI: https://doi.org/10.1140/epja/i2006-10140-7