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1.
The g-factor of the 320 keV first excited state of 51V measured by Coulomb excitation in Fe-V alloy was found to be g = 1.54±0.13.  相似文献   

2.
The average polarization of 12B produced by the capture of polarized muons in 12C has been measured using recoil implantation techniques. From the result we deduce the average polarization of the 12B ground state 12B(0) corresponding to the 12C → 12B(0) Gamow-Teller reaction: Jμ(0) = 0.43 ± 0.10. The sizeable deviation of this polarization from the value of 2/3, characteristic of a “bare” 0+ → 1+ process, is a fair evidence for induced axial-vector interaction(s) in muon capture. The ratio of the induced pseudoscalar and the axial-vector coupling constants is deduced to be: gμP/gμA = 12 ± 5.  相似文献   

3.
The decays of 48Sc and 48V have been studied with Ge(Li) diodes, scintillation spectrometers and a double focussing beta-ray spectrometer. The 3507 keV level, from which originates the quadruple cascade (9.4±0.5)% in the 48Sc decay, is also de-excited by a 1212 keV cross-over transition to the 2295 keV (4+) level and supports the assumption, that the 3507 keV level has a spin 6+. The first member of the reported triple cascade in the 48V decay is shown to be a doublet of 928.9±0.7 (1.2±0.2)% and 944.3±0.5 keV (8.0±0.5)% gamma rays, both followed by the 1311.4–983.3 keV cascade. Evidence was found, that the 2421 keV (2+) level is excited by weak gamma rays from high-energy levels. The K/β+ ration in the 48V decay is 0.69±0.05 The Q-values of 48Sc and 48V are calculated to be 3986±7 keV and if 4015±4 keV, respectively. The energy of the gamma ray of 47Sc, which is present as an impurity, is 159.2±0.5 keV.  相似文献   

4.
A C.W. multi-mode dye laser is used to obtain by optical pumping an orientation of the 2p5 3s3P0 (F = 3/2) state of 21Ne. A magnetic resonance experiment leads to the measurement of the g factor g (3P0) = 3.027 (8) × 10−4 to be compared with the theoretical prediction (3.025(6) × 10−4). One obtains also the metastability exchange cross section σ(3P0) = 18.4 ± 4 Å2 for collisions between metastable (3P0) Ne atoms and ground state Ne atoms. This result is compared with other measurements and theoretical evaluation.  相似文献   

5.
Tracer diffusion of 18O in dense, polycrystalline La1−xSrxCoO3 for x = 0.1 has been measured in the temperature range 400 to 600 °C and at 500 °C for x = 0.2 at an oxygen partial pressure of 1 × 105 Pa. Depth profiles were obtained by secondary ion mass spectrometry. The diffusion coefficient for La0.9Sr0.1CoO3 is given by D = (17–247) exp[(−232 ± 8 kJ/mole)/RT] cm2/s. This value is several orders of magnitude lower than D extrapolated from the results for x = 0.2 measured in the 700–900 °C temperature range. One possible explanation for the discrepancy is that the two measurements reflect different diffusion paths. As expected, La0.8Sr0.2CoO3 exhibits a higher diffusivity at 500 °C than does La0.9Sr0.1CoO3.  相似文献   

6.
The static quadrupole moments of the first excited Jπ = 2+ states in 20Ne and 22Ne and the reduced electric quadrupole transition probabilities of these states to the ground states were measured via projectile Coulomb excitation. The quadrupole moments were deduced from the shapes of γ-ray angular distributions. The results are: Q(20Ne, 2+) = −0.20±0.05 b and Q(22Ne, 2+) = −0.11±0.05 b. The transition strengths were deduced from yield measurements and by comparison with the yields of target γ-rays. The results are: B(E2; 0+ → 2+, 20Ne) = 0.037±0.003 e2 · b2 and B(E2; 0+ → 2+, 22Ne) = 0.025±0.002 e2· b2. The results for the transition strengths are consistent with the results of accurate timing methods and resolve discrepancies between previous experiments. The results for the quadrupole moments are consistent with earlier measurements, although the mean values we obtain are slightly lower. The experimental measurements are compared with theoretical predictions and a detailed discussion is given of corrections to this type of reorientation experiment.  相似文献   

7.
An 879.9(2) keV γ-ray transition has been identified following the β decay of 58V and assigned as the 2+1→0+1 transition in 58Cr34. A peak in the energies of the first excited 2+ states for the even–even chromium isotopes is now evident at 56Cr32, providing empirical evidence for a significant subshell gap at N=32. The appearance of this neutron subshell closure for neutron-rich nuclides may be attributed to the diminished π1f7/2–ν1f5/2 monopole proton–neutron interaction as protons are removed from the 1f7/2 single-particle orbital.  相似文献   

8.
The average g factors of high-spin states in 180,182,184Pt were measured by the transient-field technique. In all three isotopes the quasicontinuum g factor at an angular momentum of 20 is g0.37. This contrasts with similar measurements on other nuclei that have 70Z80, where typical values of g0.22 have been attributed to the influence of quasineutron alignments. Evidently proton and neutron configurations are about equally important at high spin in the Pt isotopes near mid-shell. This inference is consistent with the discrete spectroscopy, including the contention, supported by gKgR values, that h9/2 proton pairs align along with the i13/2 neutrons at rotational frequencies of ω≈0.3 MeV in 184Pt. Links between the quasicontinuum g factors and features in the discrete spectroscopy are explored by comparing and contrasting the behavior of 184Pt and 166Hf.  相似文献   

9.
We introduce a new parameterization of four-fermion operator matrix elements which does not involve quark masses and thus allows a reduction of systematic uncertainties. In order to simplify the matching between lattice and continuum renormalization schemes, we express our results in terms of renormalization group invariant B-parameters which are renormalization-scheme and scale independent. As an application of our proposal, matrix elements of ΔI=3/2 and SUSY ΔS=2 operators have been computed. The calculations have been performed using the tree-level improved Clover lattice action at two different values of the strong coupling constant (β=6/g2=6.0 and 6.2), in the quenched approximation. Renormalization constants and mixing coefficients of lattice operators have been obtained non-perturbatively. Using lowest order χPT, we also obtain ππ|O7|KNDRI=2=(0.11±0.02) GeV4 and ππ|O8|KNDRI=2=(0.51±0.05) GeV4 at μ=2 GeV.  相似文献   

10.
A report is presented on the observation of Hahn echoes from the following quadrupolar nuclei of half integer spin (I) in polycrystalline solids in the large static magnetic field gradient (37.5 T/m) which exists in the fringe field of a superconducting solenoid: 7Li, 23Na, 11B, 65Cu (I = 3/2); 27Al (I = 5/2); 51V, 59Co (I = 7/2); and 115In (I = 9/2). 23Na echo-trains from NaCl (with non-selective excitation) and from Na2SO4 (with selective excitation) are compared quantitatively for two different RF pulse sequences: 90x-(τ-90y-τ-echo-)n and 90x-(τ-90x-τ-echo-)n. The signals obtained from RF pulses corresponding to non-selective 90 ° pulses were shown to be quantitative, whereas in the selective case smaller signals were obtained since only the central transition contributed. The loss of signal from this cause can be distinguished from small signals resulting from low density of nuclei by use of the second sequence. A 7Li image obtained from LiF in a cylindrical glass-vial is shown.  相似文献   

11.
系统地研究了核磁共振碳谱(13C NMR)与化学位移规律及其定量构谱关系(QSSR).本文研究了一组多元素分子子图指数矢量(VMSG),并发现它与烷烃化学位移和(CCSA)有很好线性相关性.采用多元线性回归(MVLR)进行准确估计与预测,结果良好.  相似文献   

12.
袁晓燕  陈刚 《波谱学杂志》1999,16(5):441-447
系统地研究了核磁共振碳谱(13C NMR)与化学位移规律及其定量构谱关系(QSSR).本文研究了一组多元素分子子图指数矢量(VMSG),并发现它与烷烃化学位移和(CCSA)有很好线性相关性.采用多元线性回归(MVLR)进行准确估计与预测,结果良好.  相似文献   

13.
In this paper, the high-order perturbation formulas of spin-Hamiltonian (SH) parameters (g factors g, g and zero-field splitting D), including both the crystal-field (CF) and for the first time charge-transfer (CT) mechanisms, are established for 3d8 ions in trigonal octahedral clusters. By using these formulas, the SH parameters of Ni2+ ions in CsMgX3 (X=Cl, Br, I) crystals are calculated. The results are consistent with the experimental values. The calculations suggest that the sign of QCT (Qg, Δg or D, where the g-shift Δgi=gige, ge≈2.0023 is the value of free-electron) due to CT mechanism is the same as that of the corresponding QCF due to CF mechanism, and the relative importance of CT mechanism (characterized by QCT/QCF) increases with the increasing atomic number of ligand X. So, for the 3dn MLm clusters with ligand having large atomic number, the reasonable theoretical explanations of all SH parameters should take both CF and CT mechanisms into account. The defect structure of (NiX6)4− impurity centers in CsMgX3:Ni2+ crystals is also considered in our model.  相似文献   

14.
Angular distribution of the reaction 12C(d,τ) 11B leading to the 3/2 ground state and the 4.44 MeV excited (5/2 state 11B have measured at Ed = 80 MeV up to about 70° and 40°, respectively. The inclusion of second-order processes in the framework of CCBA calculations gives a good reproduction of the 3/2 as well as of the DWBA forbidden 3/2 angular distribution. The strong dependence of the cross section on the sign of the deformation supports a positive β2 value for 11B.  相似文献   

15.
The circular polarization of the 482 keV γ-radiation of 181Ta and the 343 keV γ-radiation of 175Lu was measured with a Compton polarimeter. Spurious effects arising from higher order contributions of quantum electrodynamics to the Compton scattering cross section were discovered. The results for the polarization are P = − (4.1±1.3)10−6 for 181Ta and P = − (1.5±6.0)10−6 for 175Lu. These values are corrected for instrument asymmetries, bremsstrahlung and intensity of other lines.  相似文献   

16.
H. Zmora  M. Blau  S. Ofer 《Nuclear Physics A》1969,130(3):541-544
The magnetic moment of the 344 keV level of 152Gd was determined from measurements of the rotations of the angular correlations of γ-γ cascades involving this level in the magnetic hyperfine field of Gd metal. The value found for gτ is (2.43±0.22)·10−11 sec.. Taking τ = (7.6±1.3)·10−11 sec, a value of 0.32±0.06 was derived for the gyromagnetic ratio of this level.  相似文献   

17.
FMR measurements have been carried out on several members of the Ln1−xSrxCoO3 (Ln = Rare earth) system. The results show that geff in these systems is around 1.25 independent of x as well as the rare earth ion. It is suggested that this unusual value of geff is due to the localized intermediate-spin Co3+ ions (t52g e1g) located at the top of the π* band.  相似文献   

18.
19.
Measurements of interaction cross sections and radii of He isotopes   总被引:3,自引:0,他引:3  
Secondary beams of 3He, 4He, 6He, and 8He were produced through the projectile fragmentation of an 800 MeV/nucleon 11B primary beam. Interaction cross sections (σI) of all He isotopes of 790 MeV/nucleon on Be, C, and Al targets were measured by a transmission-type experiment. The interaction nuclear radii of He isotopes RI(He) = (σI/π)1/2R I(T) where RI(T) is the radius of the target nucleus, have been deduced to be RI(3He) = 1.59 ± 0.06 fm, RI(4He) = 1.40 ± 0.05 fm, RI(6He) = 2.21 ± 0.06 fm, and RI(8He) = 2.52 ± 0.06 fm.  相似文献   

20.
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