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1.
The gyromagnetic ratios of the 21+, 22+, and 41+ states in 188,190,192Os were experimentally measured. It is shown that the hamiltonians of standard interacting boson models (IBM-1 and -2) fit to level spectra and B(E2) rates fail to account for either the intra-nucleus or mass-dependent g-factor variations of these states in these Os isotopes. 相似文献
2.
Dr. F. Wagner D. Kucheida G. Kaindl P. Kienle 《Zeitschrift für Physik A Hadrons and Nuclei》1970,230(1):80-88
The spectroscopic quadrupole moments and the magnetic dipole moments of the lowest 2+ states in186Os (137 keV) and188Os (155 keV) have been determined by Mößbauer transmission experiments. The electric quadrupole momentsQ 2+(Os 186)=? (1.80±0.22) b andQ 2+(Os 188)=?(1.81±0.24) b as well as their ratioQ 2+(Os 188)/Q 2+(Os 186)=1.00±0.07 within the limits of error agree withB(E2) data, if a comparison on the basis of the rotational model is made. For the g-factors and their ratio g2+(Os 186)=0.281±0.008, g2+(Os 188)=0.305±0.015 andg 2+(Os 188)/g 2+(Os 186)=1.08±0.05 was obtained. All results are compared with recent model calculations. 相似文献
3.
F. E. Wagner H. Spieler D. Kucheida P. Kienle R. Wäppling 《Zeitschrift für Physik A Hadrons and Nuclei》1972,254(2):112-126
Mössbauer transmission experiments with the 137, 155, 69 and 187 keV gamma rays of186, 188, 189, 190Os, respectively, yielded the electric quadrupole splitting of these gamma resonance lines in OsO2 and OsP2. From the results the following ratios of quadrupole moments were derived:Q 2 +(186Os, 137 keV):Q 2 +(188Os, 155keV):Q 2 +(190Os, 187 keV):Q 3/2 ?(189Os, g.s.)=(+1.100±0.020): 1.0:(+0.863±0.051): (?0.586±0.011) andQ 5/2 ?(189Os, 69 keV)/Q 3/2 ?(189Os, g.s.)=?0.735 ±0.012. The ratios for180, 188, 190Os are, within their limits of error, in agreement with the expectation of the rotational model, indicating that the pairing-plusquadrupole model calculations of Kumar and Baranger predict too rapid a transition form rotational to vibrational nuclei. Applying this argument to186Os in particular and using the measured ratios, one obtains a set of values for the quadrupole moments themselves, namelyQ 2 + (186Os)=?(1.50 ± 0.10)b,Q 2 +(188Os)=?(1.36± 0.09) b,Q 2 + (190Os)=?(1.18 ± 0.08) b,Q 3/2 ?(189Os)=+ (0.80 ± 0.06) b, andQ 5/2 ? (189Os)=? (0.59 ± 0.05) b. For the electric field gradient at Os nuclei in Re metal a value ofV zz=?(3.3 ± 0.6) · 1017 V/cm2 was found. A measurement with a magnetically split source yielded δ=+ 0.685 ± 0.025 for theE2/M1 mixing parameter of the 69 keV transition of189Os,g 5/2 ?/g 3/2 ?=0.895 ± 0.006 for the ratio of theg-factors of the 69 keV state and the groundstate, andH i=?(1135 ± 20) kOe for the hyperfine field at Os nuclei in an iron matrix. 相似文献
4.
Time-integral measurements have been made of the vacuum deorientation of the 2+ and 4+ states in 150Sm and the 6+ and 8+ states in 156Gd Coulomb-excited by 133 MeV 35Cl ions. The 150Sm results were deduced from γ-ray angular distributions measured in coincidence with backscattered 35Cl ions. In the 156Gd measurements, a fixed counter array and a sandwich target were used to measure directly the differences between the γ-ray angular distributions from nuclei recoiling in vacuum and the unperturbed γ-ray angular distributions from nuclei stopped in a thick 156Gd target. The measured deorientation time constants in ps are τ2(2+) = 27±4; τ2(4+) = 14±4; τ2(6+) = 24±3; τ2(8+) = 23+10?6; τ4(2+) = 12±2; τ4(4+) = 5±3; τ4(6+) = 7.6±2.5. The 8+ data were analyzed assuming τ2/τ4 = as predicted by the Abragam-Pound theory for essentially independently of the degree of quadrupole admixture. The other results are consistent with this except for the 2+ level which shows some quadrupole effect. The present results, which show strong deorientation of high spin levels, are in contrast to earlier work on neutron deficient Er isotopes. In light of our findings we suggest that the failure to observe deorientation in the high spin states in Er is primarily due to anomalously low g-factors associated with the backbending observed in these nuclei. 相似文献
5.
H. Spehl 《Zeitschrift für Physik A Hadrons and Nuclei》1964,179(5):482-495
The angular distributions of the deexitationγ-rays following Coulomb-excitation of the first excited 2+-states in Os188, Os190 and Os192 were measured using a metallic Target of natural Osmium. The measured attenuation coefficients areG 2(Os188)=0.798±0.013,G 2(Os190)=0.917±0.030 andG 2(Os192)=0.940±0.030. As a general test the angular distribution of the 330 keV-γ-rays of Pt194 was also measured. This distribution was found to be completely undisturbed. Assuming pure electric quadrupole interaction with the internal crystalline fields one obtains an interaction frequency ofΔv Q =eQ V zz /h=278±32 MHz for the 155 keV-state of Os188. Because the electric field gradients acting on the decaying nucleus are the same for all isotopes, one can deduce the ratio of the quadrupole moments of the excited states. The result isQ(Os188)∶Q(Os190)=1.11 ?0.19 +0.28 andQ(Os190)∶Q(Os192)=1.03±0.30. The effects of the uncertainties in the effective field gradients and their possible asymmetries on the integral attenuation factors are discussed. For 1≧G 2?0.75 these effects are found to be small. 相似文献
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8.
L.K. Fifield F.P. Calaprice C.H. Zimmerman M.J. Hurst A. Pakkanen T.J.M. Symons F. Watt K.W. Allen 《Nuclear Physics A》1977,288(1):57-81
The radiative widths for decays of the 20Ne T = 1, 2+ (10.27 MeV) state were measured by resonance α-capture in the reaction 16O(α, γ)20Ne. A special windowless gas-cell target yielded a low-background spectrum enabling six γ-branches to be observed with a Ge(Li) detector. The six branches correspond to decays from the 10.27 MeV level to the following levels: 2+(7.83 MeV), 2+(7.42 MeV), 3?(5.62 MeV), 2?(4.97 MeV), 2+(1.63 MeV) and 0+(g.s.). The branching ratios and radiative widths Γγ to these levels are: 7.83 MeV [(0.22 ± 0.06)%, 0.008 ± 0.002 eV], 7.42 MeV [(6.9 ± 0.4)%, 0.31 ± 0.04 eV], 5.62 MeV [(2.1 ± 0.2)%, 0.097 ± 0.014 eV], 4.97 MeV [(1.3 ± 0.1)%, 0.060 ± 0.008 eV], 1.63 MeV [(88.9 ± 0.5)%, 4.08 ± 0.43 eV] and 0.0 MeV [(0.64 ± 0.14)%, 0.029 ± 0.008 eV]. The radiative widths to the 1.63 MeV and 7.42 MeV levels are used to determine the CVC predictions of the weak magnetism form factors and their effects on certain β-decay observables are evaluated. 相似文献
9.
R. Kalish J.A.G. De Raedt A. Holthuizen W.A. Sterrenburg G. Van Middelkoop 《Nuclear Physics A》1978,311(3):507-517
The g-factors of the first-excited 2+ states of 144, 146, 148Nd were deduced from precession measurements in which the excited nuclei recoil through (TF IMPAC) or stop in (IMPAC) magnetized iron. The transient and static hyperfine fields which are active in these cases have been calibrated. The results for the g-factors, combined with previous data which were reanalyzed in the present work, are: g144 = 0.15 ± 0.02, g146 = 0.25 ± 0.04, g148 = 0.32 ± 0.04. The g-factor for 144Nd, which is abnormally low for a collective 2+ state, cannot be accounted for theoretically. 相似文献
10.
Rainer Link 《Zeitschrift für Physik A Hadrons and Nuclei》1974,269(2):163-171
The magnetic hyperfine interaction in several muonic atoms has been measured. The magnetic splittings of the 1s 1/2, 2s 1/2 and 2p 1/2 muon states in the 9/2+ ground state of115In, determined by measuring muonic X rays areΔE mag(1s 1/2,115In 9/2+)=3580±70 eVΔE mag(2s 1/2,115In 9/2+)=525±120 eVΔE mag(2p 1/2,115In 9/2+)=850±180 eV. The magnetic splitting of nuclearγ rays in the presence of a muon in the 1s 1/2 state yields for the 1/2? ground state in199HgΔE mag(1s 1/2,199Hg 1/2?)=468±115 eV and the following values for the first excited 2+ states in the nuclei190,192Os and200Hg:ΔE mag(1s 1/2,190Os 2+)=665± 40 80 eVΔE mag(1s 1/2,192Os 2+)=800±80 eVΔE mag(1s 1/2,200Hg 2+)=655± 75 105 eV. These data are compared with calculations using different nuclear models. 相似文献
11.
The static quadrupole moment Q21+, and the B(E2; 01+ → 2+1) value of the first excited state of26Mg have been measured using the reorientation effect in Coulomb excitation of 26Mg projectiles. It is found that Q21+ = ?13.6±3.0 (?9.5±3.0) e ·fm2 and B(E2; 0+1 → 2+1) = 322±16 (328±16) e2 ·fm4 for constructive (destructive) interference from higher states. The result for Q2 clearly differentiates among several alternative effective interactions which have been used in shell-model calculations. 相似文献
12.
N.-G. Jonsson A. Bäcklin J. Kantele R. Julin M. Luontama A. Passoja 《Nuclear Physics A》1981,371(2):333-348
0+, 2+, 44 and 3? states in 112–124Sn have been studied with the (p, p′γ) reaction and in Coulomb excitation. Absolute E2 transition rates between these levels have been extracted with the aid of the Winther-de Boer code. For 116,118Sn, B(E2; 41+ → 21+) ≈ 20 W.u., suggesting a two-phonon character of the 41+ states. For the lighter and heavier isotopes, this value is significantly smaller. All observed values of B(E2; 22+ → 21+) and B(E2; 23+→ 21+) are about 5 W.u. Also. values of B(E3; 01+ → 3?1) have been measured for all stable even Sn nuclei. In 116Sn the branching ratio (31? → 01+)/(31? → 21+) has been measured. From this we obtain a half-life of 0.34±0.07 ps for the first 3? level in 116Sn and B(E1; 31? → 21+) = (1.4±0.3) × 10?5'e2 · b, corresponding to a hindrance factor of 103. 相似文献
13.
The g-factors of the first-excited Jπ = 2+ states of 24Mg and 26Mg have been measured with the ion-implantation perturbed angular correlation technique (IMPAC). The precession of the spins of nuclei recoiling into a magnetized iron backing is predominantly caused by the transient magnetic field for these very light and short-lived (τm ≈ 1 ps) nuclei. The transient field, which attains a value of 200 T for the Mg isotopes, is present only during the slowing-down of the recoiling nucleus and results in average precession angles of about 1.5 mrad. The experimental results are treated in the framework of the transient field theory of Lindhard and Winther. This yields g-factors of g = +0.42b ± 0.09 and g = +1.3 ± 0.3 for 24Mg and 26Mg, respectively. The results are compared with theoretical predictions and for 24Mg also with a recent time-differential deorientation experiment. 相似文献
14.
A. E. Stuchbery H. H. Bolotin C. E. Doran A. P. Byrne 《Zeitschrift für Physik A Hadrons and Nuclei》1985,322(2):287-294
Gyromagnetic ratios of levels in the ground-band and of the 2 2 + state in184W were measured by means of the transient magnetic field perturbedγ-ray angular distribution technique. The levels of interest were Coulomb excited by beams of 220-MeV58Ni and63Cu ions. The results show theg-factor of the 2 2 + state to be approximately half the effectively constant value found for the ground-band levels. This disparity is compared with those previously obtained for the corresponding states in188–192Os and186W; these are discussed in the context of the interacting boson model. 相似文献
15.
A. E. Stuchbery H. H. Bolotin C. E. Doran I. Morrison L. D. Wood H. Yamada 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(4):669-674
The gyromagnetic ratios of the 4 1 + , 6 1 + , and 2 2 + states in186W were measured relative to that of the 2 1 + level by means of the transient field implantation perturbedγ-ray angular distribution technique. The nuclei in the states of interest were Coulomb excited using a beam of 220-MeV63Cu projectiles and recoiled swiftly through a thin, polarized Fe foil. The present measurements yielded ratiosg(4 1 + )/g(2 1 + )=1.04±0.07,g(6 1 + )/g(2 1 + )=1.03 ±0.20 andg(2 2 + )/g(2 1 + )=0.63±0.13. The sizable disparity between the measuredg-factors of the ground- and excited-band is examined within the context of the interacting boson approximation model. 相似文献
16.
N. Kawamura K. Iura Y. Kimura K. Katsube M. Kikuchi S. Ali S. Hayashibe T. Ishimatsu M. Fujioka K. Abe 《Nuclear Physics A》1983,406(3):533-540
The nuclear g-factor of the 4498 keV + isomeric state in 63Cu was measured with the in-bearn perturbed angular distribution method, through the 62Ni(α, p2nγ)63Cu reaction, to be gexp = 0.184 ± 0.012. This value is in good agreement with a semiempirical g-factor for the three-quasiparticle configuration [π2p(v1f, 1g)7]+ calculated using the experimental single-particle g-factors of neighbouring nuclei. At the same time the internal magnetic field at the Cu nuclei in Ni metal was obtained to be Bint = ?46.6 ± 1.3 kG. 相似文献
17.
The branching ratios of E0 and E2 transitions depopulating the 0+2 and 0+3 states in 70Ge have been studied using conversion-electron and γ-ray spectroscopy, as well as a new internal-pair measurement technique. A value of 3.7 (2) ns has been obtained in a remeasurement of the half-life of the 0+2 state. Two new E0 transitions, 0+3 → 0+2 and 0+3 → 0+1, have been observed. A comparison of the measured X(E0/E2), ρ2(E0) and B(E2) values for the excited 0+ states in 70Ge with the corresponding 150Sm data supports a recent shape-coexistence interpretation of the even-mass Ge isotopes. 相似文献
18.
S.M. Burnett A.M. Baxter S. Hinds F. Pribac R.H. Spear W.J. Vermeer 《Nuclear Physics A》1985,432(2):514-524
Reduced transition probabilities, B(E2) and B(E3), have been measured for low-lying 2+ and 3? states in 132, 134, 136, 138Ba using Coulomb excitation by 40 MeV 12C ions. The B(E2) values are in general consistent with previous measurements and the B(E3;0+ → 31?) values are 0.176 ± 0.022, 0.148 ± 0.018, 0.155 ± 0.018 and 0.133 ± 0.013 e2 · b3 for 132, 134, 136, 138Ba respectively. These B(E3) values correspond to about 24 to 17 W.u. and such enhancements suggest that these 3? states have an essentially collective character which may be attributed to octupole vibrations. 相似文献
19.
By integral perturbedγ-γ-angular correlation the gyromagnetic ratios of a 2-quasi-particle state at 1,513 keV and the 4+ state of the ground state rotational band in156Gd were measured, using sources prepared by159Tb(γ, 3n) and156Gd(d, 2n) reactions:g 1;513 keV 4+ =0.78±0.05;g R 4+ =0.37±0.05. In addition we obtain the multipole mixing ratiosδ 535 keV(M2/E1)=?0.09±0.01;δ 1,225 keV(E2/M1)=+1.83±0.10 for the 535 keV and 1,225 keVγ-rays. The classification of the 1,513 keV state is discussed. The internal field of Gd in Tb metal at 77 °K was found to beH=(?192±16)kOe. 相似文献
20.
C. Roulet G. Albouy G. Auger J.M. Lagrange M. Pautrat K.G. Rensfelt H. Richel H. Sergolle J. Vanhorenbeeck 《Nuclear Physics A》1977,285(1):156-166
The g-factor of the 12+ isomeric state in lead isotopes with A = 194, 196, 198 was measured using the time-differential perturbed angular distribution method (TDPAD). The values obtained are respectively g(194) = ?0.158(6); g(196) = ?0.157(7); g(198) = ?0.144(11). A more precise determination of the 12+ level half-life is also made. The g-factprs of these nuclear states, which are described with v(i)?2 as the main configuration, are surprisingly constant over a large mass range (between A = 206 and 194). A core polarization analysis explains this trend: the polarization induced on neutrons in i orbit decreases with the mass number A (blocking effect), but a compensation is provided by the other spin-orbit partners f-f and P-P. 相似文献