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1.
The laser-atomic-beam spectroscopy has been used to make precise measurements of the hyperfine structure in transitions starting from metastable states of the configuration 4f 125d6s 2 in169TmI. With the resulting experimental magnetic dipole hyperfine constantsA J andA J values from former investigations a parametric analysis of the hyperfine structure in the configurations 4f 136s6p and 4f 125d6s 2 has been performed using wavefunctions from fine structure calculations. A comparison of theoretical and experimental hyperfine constants allowed a test of the reliability of the wave-functions used. The hyperfine parameters respectively hyperfine radial integrals determined from the analysis were compared with corresponding data from ab initio calculations for the ground configuration in TmI.  相似文献   

2.
A survey of hyperfine analyses in the low-lying configurations 4f n 6s 2, 4f n 5d6s, 4f n 6s6p, and 4f n?1 5d6s 2 of the lanthanides is given. Experimental hf radial integrals 〈r ?3 nl kj are indicated for the configurations under investigation. From a comparison of experimental and theoretical hf radial integrals configuration-interaction contributions Δ nl kj to the hfs have been evaluated for the configurations for which corresponding integrals were available. With nuclear electric quadrupole moments from muonic x-ray investigations and radial integrals 〈r ?3 nl 01 and 〈r ?3 nl 02 from experimental hfs quadrupole shielding correctionsR nl 01 have been obtained. The variation of hyperfine radial integrals, configuration-interaction contributions and quadrupole shielding corrections over the 4f shell in the configurations under study is discussed. Trends of these quantities in different configurations are compared.  相似文献   

3.
The high resolution laser-atomic-beam technique was used to investigate the hyperfine structure in Nd I 4f 4 5d6s 7 L, 7 K, 7 I, 7 H, 7 G, 5 L, 5 K, and 5 I for both of the stable odd isotopes. The metastable states were populated by an arc discharge burning in the atomic beam, and 31 transitions to higher odd levels have been studied. Knowledge of the hyperfine constants of 34 levels of 4f 4 5d6s allowed a comprehensive parametric analysis to be performed, using the effective tensor operator formalism. Compared to earlier analyses, a significant reduction of errors has been achieved for all the parameters. The contact parameter a 4f 10 has been fitted freely, thus providing an experimental value for the core-polarization effects. They are about six times larger than the relativistic effects.  相似文献   

4.
Radiative lifetimes of the 4f 7 (8 S) 6s 6p z 10 P 7/2, 9/2,z 8 P 5/2, 7/2, 9/2 andz 6 P 7/2, 5/2 levels of Eu I were measured by the time resolved recording of the exponential decay of the fluorescence. Three of them were measured for the first time, the others agree with previous determinations. From the values of the lifetimes absolute oscillator strengths are deduced, taking into account the branching ratios for the transitions to the 4f 7 6s 2 and 4f 7 5d 6s levels. From these absolutef values the radial integralI(6s 2, 6s 6p) was derived by a parametric analysis. Theoretical values of oscillator strengths which were calculated using this radial integral show good agreement with the experimental data.  相似文献   

5.
Hyperfine constants of low lying levels of the configuration 4f 115d6s 2 in Er I have been measured for the only stable odd isotope,167Er, using high resolution laseratomic-beam spectroscopy. Hyperfine parameters were evaluated from the experimental data using the effective tensor operator formalism. For this purpose eigenfunctions have been determined from an analysis of the fine structure energies of Er I as well as from ab initio multiconfiguration Dirac-Fock calculations. With the latter method also ab initio hyperfine constants for the levels investigated were evaluated. A comparison of calculated fine structure energies, Landég J -factors and hyperfine constants with the experimental data allowed a test of the reliability of the fine structure and multiconfiguration Dirac-Fock wavefunctions. Effective nuclear electric quadrupole moments for167Er have been determined from the experimental hyperfine constants using both calculated relativistic electronic radial integrals and hyperfine parameters for the 4f and 5d electrons in the configuration 4f 115d6s 2 in Er I. From a comparison with the nuclear quadrupole moment measured in the mesic atom Sternheimer shielding factors are calculated. Configuration-interaction contributions to the radial integrals 〈r ?3 nl 01 of the 4f and 5d electrons have been determined.  相似文献   

6.
The investigation of the isotope shift (IS) and hyperfine structure (hfs) is extended from Eu 4f 7 6s7s to the complete configuration 4f 7 6s8s, by means of the transitions 432.3, 456.5, 463.0 and 493.8 nm to 4f 7 6s6p. A thorough experimental and theoretical analysis — including two further lines 492.8 and 498.7 nm from 4f 7 5d 2 — is carried out which e.g. confirms former fine structure calculations of one of us (J.F.W.) concerning some reclassifications. The discussion of the IS of the four levels (4f 7)6s8s with the sharing rule manifests again the need for inclusion of crossed-second-order effects. For the parameters we evaluated:g 3(4f, 6s)=?1, 2(2) mK andd=79, 3(1.0) mK. The ratiog 3/G 3=?5, 9(1.0)·10?6 is again in full agreement with those found by us in other Eu configurations. The single electron hfs splitting constantsa 4f 10 =?2, 3(4) mK,a 6s 10 =389(4) mK anda 8s 10 =49 (4) mK were also evaluated and compared to those found in 4f 7 6s7s.  相似文献   

7.
The hyperfine spectra of the 5s4d 3 D 1-5s20f, 5s4d 3 D 2-5s23f, and 5s 4d 3 D 3-5s32f transitions of87Sr (I=9/2) have been measured by collinear fast beam laser spectroscopy. The structure in the upper configurations is highly perturbed by fine structure splitting that is of comparable size to the hyperfine interaction energy. These perturbations can be adequately treated with conventional matrix diagonalization methods, using the 5s-electron magnetic dipole interaction terma 5s and the unperturbed fine structure splittings as input parameters. Additionally, hyperfine constants for the lower 5s4d 3 D configurations, including theA- andB-factors and a separation of the individuals- andd-electron contributions to these factors, are derived.  相似文献   

8.
The quadratic Stark effect in the hyperfine structure of all levels of the configuration 4f 7(8 S)6s6p in europium I, which can be excited by electric dipole radiation from the ground state, has been investigated by laser-atomic-beam spectroscopy. From the measured shifts and splittings of the hyperfine components the scalar and tensor polarizabilities have been deduced. From the polarizabilities radial integrals for electric dipole radiation were determined by a parametric analysis. With these radial integrals theoretical values of the polarizabilities were calculated.  相似文献   

9.
In the Eu I configuration 4f 7 6s6d the isotope shift (IS) and hyperfine-structure (hfs) of the termse 6 D ande 10 D were determined from fourteen transitions (4f 7 6s6d-4f 7 6s6p) with computer supported interference spectroscopy. From the IS of altogether nine levels of 4f 7 6s6d the crossed-second-order-parameterg 3(4f,6s)=?0.90(6)mK was evaluated. The ratiog 3/G 3=?4.4(3)·10?6 (G 3: Slater Integral of the fine structure) is of the same size as that from five other independent investigations and one theoretical value. The single electron hfs splitting constantsa 4f 10 =?1.9(3)mK,a 6s 10 =391(3)mK, anda 6d 12 =0.9(3)mK were also evaluated and are compared with those of other Eu 4f 7 6snl configurations.  相似文献   

10.
The hyperfine structure (hfs) and the isotope shift (IS) of transitions between metastable levels of the configuration 4f 7 5d 6s and levels of the configuration 4f 6 5d 6s 2 of151Eu and153Eu were studied by means of the high resolution laser-atomic-beam technique. New data for the hfs in151Eu and153Eu were obtained as well as new and more accurate for the IS between151Eu and153Eu. The measured hfs constantsA andB of the 4f 6 5d 6s 2 configuration allow to perform a parametric analysis using the Sandars and Beck theory. The value of the Sternheimer correction is also disscused.  相似文献   

11.
12.
Doppler-free saturation absorption spectroscopy was applied on an atomic thulium vapour in a see-through hollow cathode for the determination of precise values for the magnetic dipole hyperfine structure constantsA of 6 levels of the configuration 4f 13 6s7s. A parametric analysis of the hyperfine structure has been performed, using wave-functions from a fine structure calculation, which leads to one-electron hyperfine structure parametersa 4f 01 =?500(6) MHz,a 6s 10 =?5058(47) MHz, anda 7s 10 =?1012 MHz.  相似文献   

13.
We report the hyperfine structure (hfs) measurement of the metastable (3d 6 4s 2)a 3 H 4, 5, 6 states of57Fe. The kHz-precision of these experimental results together with the hyperfine structure values of (3d 6 4s 2)a 5 D 1, 2, 3, 4, (3d 7 4s)a 5 F 2, 3, 4, 5, and (3d 7 4s)a 3 F 2, 3, 4, which were measured earlier, allowed to determine a very detailed set of effective radial parameters describing the hfs of these states, using a new parametrization method. This method treats one- and two-body contributions to the hfs separately. In this way configuration interaction effects in the hfs of the57Fe atom can be studied in detail and compared with configuration interaction effects in the fine structure of the same atom.  相似文献   

14.
The isotope shift between all stable neodymium isotopes has been measured for 21 transitions in the Nd I spectrum by means of laser-atomic-beam absorption spectroscopy. A parametric analysis of the observed shifts in all the levels of the terms5 I,5 F, and5 S of the ground configuration 4f 46s 2 yields not only the magnetic parameterz 4f but, for the first time, also the effective electrostatic parametersa,b, andc. A more accurate value of the nuclear parameter 148,150 (Nd)=0.369(20) fm2 is obtained from the investigation of a 4f 35d6s 2–4f 35d6s6p transition. The comparison of non-relativistic Hartree-Fock calculations with the experimental data yields a scaling factorS I * (Nd)=1.50(9) that agrees with the corresponding one from the hyperfine structure analysis.  相似文献   

15.
The energies of all the levels of Nd I 4f 4 6s 2 5 F and of5 S 2 as well as of 4f 4 5d 6s 7 H 2 have been determined by means of laser-induced fluorescence in a hollow cathode. Their interpretation was carried out with the use of hyperfine structure data and a new parametric calculation of (4f 4 6s 2 + 4f 4 5d 6s). Furthermore, the energies andJ values of 5 new odd levels were found.  相似文献   

16.
A systematic study of the Stark splitting of the 4f N 6s 2 ground levels in the lanthanides was performed by the nonlinear level-crossing technique and the optical pumping method with rf detection in parallel electric and magnetic fields. The tensor polarizabilities of the hyperfine structure levels in141Pr I,159Tb I,165Ho I,169Tm I and of the fine structure levels in142Nd I,164Dy I, and166Er I were deduced from the level-crossing and rf signals. Values of the tensor polarizability of the 4f electron were evaluated from the experimental results. On average these values decrease with the increasing number of 4f electrons from the value of141Pr (4f 3 6s 2) α2(4f)=1.16(12) kHz/(kV/cm)2 to the value of169Tm (4f 136s 2) α2(4f)=0.68(4) kHz/(kV/cm)2. This decrease is caused by the lanthanides contraction.  相似文献   

17.
Using Doppler-reduced laser induced fluorescence spectroscopy in an atomic beam, the hyperfine structure of 22 levels of the configuration 4f 135d6s6p in neutral ytterbium has been investigated for the two odd isotopes 171 Yb and 171 Yb. The experimental results have been used in a study of the hyperfine structure in regard to a determination of the one-electron parameters for the magnetic dipole and the electric quadrupole hyperfine coupling of the isotope 173 Yb in part II of this work.  相似文献   

18.
A Laser Induced Fluorescence experiment in an atomic beam has yielded experimental values of hyperfine structure (hfs) constants A and B for 28 low odd levels and 22 even levels, with an accuracy around 10–5 cm–1 for A and 10–3 cm–1 for B. A Condon Slater Racah parametric interpretation of the hfs data concerning 22 of these levels, on the basis of the configuration 5f 3 6d 7s 2, has provided values of monoelectronic parametersa 5f 01 ,a 5f 12 ,a 6d 01 ,b 5f 02 ,b 6d 02 ,b 6d 13 . A least square fit calculation has been compared to the values deduced from Dirac-Fock monoelectronic radial integrals. The fit represents 18 A (16 B) values ranging from –0.42 to –2.96 mK (from –41 to 156 mK) with discrepancies less than 0.2 mK (8 mK).  相似文献   

19.
20.
Systematic study of hyperfine structures, Zeeman and Stark effects in Sm I is performed for the lowest 7G1-6 levels belonging to the configuration 4f 66s6p by atomic-beam laser spectroscopy with fluorescence detection. The hyperfine coupling constants of 7G2-6 levels are determined. From the Zeeman splittings for the 4f 66s 2 7F2-6 ? 4f 66s6p 7G2-6 transitions, g-values are determined for the 7G2.6 levels and the precision is improved by several orders of magnitude. From the Stark splittings for the 7F0-3 ? 7G1-3 transitions, tensor polarizabilities α 2(J) are determined for the upper 7G1-3 levels. Particularly for the 7G1 level (15 650.55 cm?1) which has close-lying opposite-parity level, the isotope dependence of α 2(J) is clearly observed for the first time.  相似文献   

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