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Hyperfine structures and isotope shifts of the transition 4f7(8S 7 2/0 )6p3/2 (7/2,3/2)4?4f7(8S 7 2/0 ) 5d9D 4 0 ,λ=604.95 nm, of stable151Eu and153Eu and radioactive152Eu and154Eu have been investigated by collinear laser — ion beam Spectroscopy. Nuclear quadrupole moments have been derived.  相似文献   

3.
Keim  M.  Georg  U.  Klein  A.  Neugart  R.  Neuroth  M.  Wilbert  S.  Lievens  P.  Vermeeren  L. 《Hyperfine Interactions》1996,97(1):543-550
The nuclear quadrupole moments of neutron-rich sodium isotopes are being investigated with the help of in-beam polarization by optical pumping in combination with-NMR techniques. First measurements have yielded the quadrupole splittings of NMR signals in the lattice of LiNbO3 for the isotopes26Na,27Na and28Na. Interaction constants and ratios of the electric quadrupole moments are derived. In view of future experiments,-decay asymmetries for the sequence of isotopes up to theN=20 neutron shell closure,26–31Na, have been measured.  相似文献   

4.
The β-NMR (nuclear magnetic resonance) and β-NQR (nuclear quadrupole resonance) technique and its ex-perimental set-up have been developed for the first time in China. The lifetime, magnetic moment and spin polarization of ^12B were determ/ned. The experimental results show the reliability of this newly developed β-NMR and β-NQR set-up.  相似文献   

5.
The -NMR technique has been modified in order to detect efficiently the nuclear quadrupole effects in the NMR spectra. -NMR is detected as a function of coupling frequency; all RFs that correspond to the coupling frequency were applied simultaneously.  相似文献   

6.
The application of laser spectroscopy methods for a detailed investigation of nuclear moments and charge radii of halo nuclei has been restricted to only a few cases. Three such experiments are discussed, showing the potential of these methods for research on the nuclear halo structure. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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The paper reports that the isotope shift between natural uranium isotope 235and 238 and the hyperfine sturcture width width of U~(235) were measured by means of laser-in-duced fluorescence spectroscopy.The A and B hyperfine structure splitting constants of U~(235)were also given for 14643 cm~(-1),15720 cm~(-1)and 15631 cm~(-1) levels.  相似文献   

9.
NMR spectra of12B in Pt (fcc) metal were observed by use of the -NMR detection method. A sharp single line was observed by use of an annealed Pt foil for the implantation medium. The dipolar broadening has been determined to be 332±30 Hz (HWHM).  相似文献   

10.
Hydrogen Lyman-α radiation (121.56 nm) is important because it allows for the excitation and detection of ground-state hydrogen atoms by a one-photon process. The trapping of antihydrogen, recently reported by the ALPHA collaboration at CERN, has revived interest in Lyman-α lasers. In order to perform high precision tests of matter-antimatter symmetry violations or gravity-antimatter interactions with antihydrogen, laser cooling using the 1s ? 2p single photon transition is essential. Recent theoretical simulations predict that even with a pulsed Lyman-α source, laser cooling of antihydrogen would be possible. Here we describe the implementation of a high power vacuum-ultraviolet (VUV) laser at the Lyman-α transition of hydrogen. The VUV light was generated using a two-photon-resonant four-wave mixing process in a phase-matched mixture of krypton and argon. Two wavelengths (ω R → 202.31 and ω T → 602.56 nm) were mixed in a sum-difference scheme (ω VUV = 2ω R ? ω T ) with a two-photon resonance at (4s 24p 55p[1/2]0 ← 4s 24p 6(1S 0)) transition in Kr. With an Ar/Kr mixture of 3.9:1 we obtained 10 ns pulses of 0.1 μJ of energy at a repetition rate of 10 Hz.  相似文献   

11.
The nuclear quadrupole moment of8B(I =2+,T 1/2=769 ms) has been determined by use of a modified -NMR detection as |Q(8B)|=68.3±2.1 mb. A field gradient was obtained in a single crystal Mg at room temperature.  相似文献   

12.
A pair of parallel Stark plates are added to a CO laser magnetic resonance spectrometer to apply electric field in the absorption cell. This apparatus is used to measure the molecular electric dipole moment via Zeeman and Stark effects simultaneously. The saturated absorption spectra of NO (X2Π3/2, ν = 1 ← 0) was observed and the electric dipole moments of NO were directly measured in the presence of an electric field. The dipole moments are determined as μ0(ν = 0) = 0.1595(15) D, μ1 (ν = 1) = 0.1425(16) D. The electric dipole moment of the vibrationally excited state (ν = 1) is determined for the first time. The dependence of the electric dipole moments on its nuclear distances is interpreted.  相似文献   

13.
《Infrared physics》1985,25(1-2):525-529
Nuclear β-decays that are forbidden by angular momentum and/or parity selection rules can be significantly enhanced by external electromagnetic fields. The effect is largely nonperturbative in nature, with a governing intensity parameter that becomes larger at long wavelengths. FIR radiation is a focus of interest for inducing the effect. An examination is done here of the field-dependent terms which lead to forbiddenness removal in β-decay. These terms come primarily from field interaction with the initial and final nuclear charges, and from the longitudinal field interaction term for the β-particle. Relevant astrophysical environments are discussed in which the effect can occur.  相似文献   

14.
The results of theoretical and experimental investigations of delocalization of nuclear polarization in spatially disordered media are presented. The experiment is based on the measurement of a depolarization of β-active 8Li impurity nuclei (β-nuclei) in the spatially disordered subsystem of 8Li-6Li nuclei in LiF single crystals. The process is determined by the dipole-dipole interaction in this subsystem and by its dipole interactions with nuclei of the 7Li19F matrix. It is effective in a wide range of external magnetic fields H 0 = 200–3000 G owing to proximity of g-factors. The kinetics of a depolarization of β-nuclei at the 6Li concentration c = 0.15–10.06% in fields H 0 = 200 and 1210 G is investigated. A satisfactory explanation of the results is based on the numerical-analytical simulation of the process.  相似文献   

15.
The facilities of the coherent laser pulse spectroscopy of the ¯pHe+ transitions are considered taking the magnetic structure of the energy levels into account. The possibility for the observation of the dynamics of intramolecular motions is also analyzed.  相似文献   

16.
Various experimental methods, used in Chair of Quantum Engineering and Metrology for determination of the hyperfine structure of electronic levels in lanthanides atoms and ions, are presented. In turn the spectroscopic methods on an atomic beam (laser induced fluorescence and laser-rf double resonance ABMR-LIRF), laser-rf double resonance in a Paul trap and spectroscopic methods in a hollow cathode discharge (optogalvanic detection and laser induced fluorescence) are presented. Each method has been characterized with its potential accuracy and domain of application. The results achieved for the atoms and the ions of lanthanum, praseodymium, neodymium and europium have been published in numerous articles (compiled in the reference list).  相似文献   

17.
The nuclear electric quadrupole moments of the isotopes 26Na, 27Na, 28Na and 29Na were measured by -NMR spectroscopy in single crystals of LiNbO3 and NaNO3. High degrees of nuclear polarization were produced by optical pumping of the sodium atoms in a fast beam with a collinear laser beam. The polarized nuclei were implanted into the crystals and NMR signals were observed in the -decay asymmetries. Preparatory measurements also yielded improved values for the magnetic moments of 27-31Na and confirmed the spin I=3/2 for 31Na. The results are discussed in comparison with large-basis shell model calculations. Received: 1 February 2000 / Accepted: 3 April 2000  相似文献   

18.
A·C mismatches are studied by Raman spectral characterization of PolyA,PolyC,and their equimolar complex in solution of 0.14 mol/L Na~ ,pH7.0.Experimental results show that A·C mismatches occur to be A/B(mainly A)conformers,and unlike Watson-Crick base pairing,this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H_2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger,and conformation of the backbone more ordered,which leads to obvious Raman hypochromic effect with some shifts in corresponding bands.  相似文献   

19.
《Nuclear Physics A》1997,625(3):521-553
The gross theory of β-decay is refined to take into account shell effects of the parent nuclei, and the resulting theory is named semi-gross theory. In this theory, the one-particle energy distribution in the parent nucleus is taken to have structures, and the one-particle strength function is assumed to depend on the quantum numbers of the initial state of the decaying nucleon. β-decay (partial) half-lives are calculated for 1659 nuclides, and the results are compared with experimental data as well as with those calculated by the gross theory. The β-decay strength functions are shown for two selected nuclides, and briefly discussed. These numerical studies confirm that the semi-gross theory includes some part of the shell effects correctly, although there still remain deviations of the theoretical results from experimental data, which should, at least partly, be due to shell effects of the daughter nuclei. Comparison of the present results with microscopic theories shows that the overall accuracy of the semi-gross theory is comparable with those of the microscopic theories.  相似文献   

20.
The spectral resolved femtosecond pump-probe experiment is applied to measure the third order nonlinear refractive index coefficient, two-photon absorption coefficient of GaP crystal, and the chirp parameter of the input laser pulses. The results show that nonlinear refractive index coefficient is 2 × 10 -18 m2/W, two-photon absorption coefficient is 2×10-11 m/W at wavelength of 783.5 nm, and the chirp parameter of laser pulse is 1×1025 s-2. Furthermore, the mechanism of nonlinear refraction due to two-photon absorption in GaP crystal and experimental results are discussed.  相似文献   

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