Evidence for a nuclear hexadecapole interaction in the hyperfine spectrum of LiI (original) (raw)
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An anomaly in the isotopomer shift of the hyperfine spectrum of LiI
The Journal of Chemical Physics, 2005
A high-precision examination of the hyperfine spectrum of 6 LiI in comparison with 7 LiI shows a shift in the iodine nuclear electric quadrupole moment that cannot be accounted for by a model in which the electric field gradient at the iodine site is assumed to depend only upon the internuclear distance between Li and I. The other hyperfine interactions are consistent between the two isotopomers, including the previously reported electric hexadecapole interaction of the iodine nucleus.
New measurement and reevaluation of the nuclear magnetic andquadrupole moments of Li8 and Li9
Physical Review C, 2005
The nuclear magnetic moment of 9 Li and the quadrupole moments of 8 Li and 9 Li have been measured using β-asymmetry detection of nuclear magnetic resonance (β-NMR) on optically polarized beams at ISOLDE/CERN. The radioactive beams were implanted in Si for g factor measurements and in Zn, LiNbO 3 , and LiTaO 3 crystals for quadrupole moment measurements. The electric field gradient V zz = 4.26(4)×10 15 V/cm 2 is deduced for Li in Zn. Using a recently adopted reference value Q( 7 Li) = −40.0(3) mb, we reevaluated all earlier reported nuclear quadrupole moments of 8 Li and 9 Li. Based on all available previous and present data, the adopted quadrupole moments for these isotopes are Q( 8 Li) = +31.4(2) mb and Q( 9 Li) = −30.6(2) mb. The magnetic moment of 9 Li is deduced as µ( 9 Li) = 3.43678(6)µ N . The values are compared to predictions from shell-model and cluster-model calculations.
Journal of Molecular Spectroscopy, 1990
The 'Li, 6Li, and 'H quadrupole coupling constants of rovibrational levels of 'Li 'H+, 6Li 'H +, 'Li'H+, and 6Li2Hf in their three lowest-lying *Z+ electronic states have been calculated from molecular wave functions which explicitly describe nuclear displacement. The electronic excitation is predicted to lead to a significant increase in the strength of the Li coupling. The deuteron and 6Li coupling is found to be weak in all the electronic states. The vibrational dependence of the nuclear quadrupole coupling constants is found to be quite significant for all the isotopomem studied. The rotational dependence is predicted to be unimportant. The main features of the quadrupole coupling data are compared with those for the isotopic species of LiH in their X'Z+ and A 'Z + electronic states. Special attention is paid to relative magnitudes of the Li and D quadrupole coupling constants in the 'Li2H ' and 'Li *H + isotopic variants and to their changes with electronic, vibrational, and rotational excitation. The information about the changes is used to outline an approach to interpretation of the hypertine structure of the spectra of these isotopic species. A qualitative difference among the X ?Z+, 2 'Z+, and 3 'Z + quadrupole hyperfine patterns of 6Li2H+ is predicted. 0 1990 Academic press, hc.
International Journal of Quantum Chemistry, 1990
The 2H, 6Li, and 7Li quadrupole coupling constants of the low‐lying rovibrational levels in the X1∑+ and A1∑+ electronic states of 7Li2H, 6Li2H, 7Li1H, and 6Li1H are calculated from molecular wave functions which explicitly describe nuclear motion. Except for the lithium coupling constants in the A1∑+ state, the vibrational dependence of the nuclear quadrupole coupling is found to be significant for all the studied isotopic species. On the other hand, the rotational dependence appears to be important only for the deuteron coupling constant of 7Li2H and 6Li2H in the A1∑+ state. Special attention is paid to relative magnitudes of the Li and D quadrupole coupling constants in the 7Li2H and 6Li2H isotopic species. The information about the relative magnitudes and their changes with vibrational excitation is used to outline a theoretical approach to the interpretation of the hyperfine structure of the spectra of these species.
Nuclear electric quadrupole moment of6Li
Physical Review A, 1998
The molecular beam electric resonance technique has been used to examine the hyperfine spectrum of 6 Li 19 F for the purpose of obtaining an improved value of the ratio of the electric quadrupole moments of the two lithium nuclei. A total of 29 transitions in vibrational states 0-2 and rotational states 1-4 have been included in a fit to determine the Li nuclear quadrupole interaction along with the magnetic spin-rotation and spin-spin interactions. The magnetic interactions are consistent with values calculated from the previously reported 7 Li 19 F values, but those have been refitted to take advantage of the new information from 6 Li 19 F. The electric quadrupole moment ratio of the two lithium isotopes determined from measurements on the two forms of LiF is Q(6 Li)/Q(7 Li)ϭ0.020 161Ϯ0.000 013 ͑one standard deviation estimate͒. ͓S1050-2947͑98͒08504-7͔
Invariant-mass spectroscopy of 10Li and 11Li
Nuclear Physics A, 1997
Break-up of secondary l~Li ion beams (280 MeV/nucleon) on C and Pb targets into 9Li and neutrons is studied experimentally. Cross sections and neutron multiplicity distributions are obtained, characterizing different reaction mechanisms, lnvariant-mass spectroscopy for l~Li and l°Li is performed. The E1 strength distribution, deduced from electromagnetic excitation of llLi up to an excitation energy of 4 MeV comprises ,-,8% of the Thomas-Reiche-Kuhn energy-weighted sumrule strength. Two low-lying resonance-like structures are observed for l°Li at decay energies of 0.21(5) and 0.62(10) MeV, the former one carrying 26(10)% of the strength and likely to be associated with an s-wave neutron decay. A strong di-neutron correlation in llLi can be discarded. Calculations in a quasi-particle RPA approach are compared with the experimental results for l°Li and JlLi. (~) 1997 Elsevier Science B.V. 0375-9474/97/$17.00 (~ 1997 Elsevier Science B.V. All fights reserved. PH S0375-9474(97) 00134-6
International Journal of Quantum Chemistry, 2010
The vibrational g factor, that is, the nonadiabatic correction to the vibrational reduced mass, of LiH has been calculated for internuclear distances over a wide range. Based on multiconfigurational wave functions with a large complete active space and an extended set of gaussian type basis functions, these calculations yielded also the rotational g factor, the electric dipolar moment, and its gradient with internuclear distance for LiH in its electronic ground state X 1Σ+. The vibrational g factor gv exhibits a pronounced minimum near internuclear distance R = 3.65 × 10−10 m; the derivative of electric dipolar moment and the nonadiabatic matrix element coupling the electronic ground state to the first electronically excited state exhibit extrema near the same location that is also near the avoided crossing of the curves for potential energy for the electronic ground state and excited state A 1Σ+. The irreducible contribution g(R) to the rotational g factor increases monotonically over the calculated domain, whereas the irreducible contribution g(R) to the vibrational g factor has a minimum at the same location as that of gv itself. From these calculated radial functions, we derived values of the rotational g factor and electric dipolar moment for LiH in vibrational states v = 0 and 1, and the corresponding rotational dependences, in satisfactory agreement with experimental values. These calculated data of rotational g factor served as constraints in new fits of 1000 vibration-rotational spectral data of LiH in four isotopic variants, which yield estimates of adiabatic corrections for comparison with published data and of the vibrational g factor for comparison with our calculated results. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Precision Measurement of Li11 Moments: Influence of Halo Neutrons on the Li9 Core
Physical Review Letters, 2008
The electric quadrupole moment and the magnetic moment of the 11 Li halo nucleus have been measured with more than an order of magnitude higher precision than before, jQj ¼ 33:3ð5Þ mb and ¼ þ3:6712ð3Þ N , revealing a 8.8(1.5)% increase of the quadrupole moment relative to that of 9 Li. This result is compared to various models that aim at describing the halo properties. In the shell model an increased quadrupole moment points to a significant occupation of the 1d orbits, whereas in a simple halo picture this can be explained by relating the quadrupole moments of the proton distribution to the charge radii. Advanced models so far fail to reproduce simultaneously the trends observed in the radii and quadrupole moments of the lithium isotopes.
Nuclear Physics A, 1983
The y-decay of 41 and strengths of 40 %S(p, Y)~~CI resonances were studied for E, < 2.0 MeV. The excitation energies of 37 and the ydecay of 41 bound levels were determined. The Q-value of the reaction was found to be Q = 5142.5kO.2 keV. Spin and parity assignments J" = 2, 2+ and 2-were made to the bound states at E, = 4.14, 4.33 and 4.42 MeV and the spin and parity of six bound levels were restricted to two values. Mean lifetimes of 17 bound levels were measured by means of the DSA technique. The spins and/or parities of eight resonances were unambiguously determined from y-ray angular distributions and strengths. NUCLEAR REACTIONS 33S(p,y), E = 0.4-2.0 MeV; measured b(Er. Er), Q, E,, I,(@), E DSA. 34Cl levets deduced, resonance strengths, y-branchings, 7& J, x. Enriched targets. ' Rijksuniversiteit, Utrecht, The Netherlands. ') J" and T for resonances from table 2. d, rY for the resonance levels was calculated from the resonance strengths in table 1. ') The parity assignment is from ref. 13). ') rY for the E, = 3.33 MeV level was calculated from the mean lifetime given in ref. 3). ') The parity assignment is from ref. t5). h, The J" = (2,3+) assignment from angular correlation measurements s) and the decay of the level. ') The J" possibility which led to the lowest multipolarity was used.