R. Winkler

Electric and magnetic hyperfinestructure investigations in the 5s25p3 and 5s25p26s Configurations of121, 123Sb

Optical hyperfinestructure investigations in several spectral lines were carried out in the Sb-I spectrum from which for the first time accurate values of the hfs-splitting constantsA andB of the ground configuration 5p3 and also for five of the eight levels of the first excited configuration 5p26s were obtained. With these parameters the influence of core polarization effects is calculated to beac= −6.6(4) mK, (equivalent to a magnetic field of −283(20) kG perp-electron spin). The quadrupole momentQ121= −0.36(4) b (including Sternheimer correction) was obtained with the experimental valuesb3/2= −14.3(1.0) mK and 〈r−3〉 =11.2(3) a.u. andQ123= −0.49(5) b withb3/2= −19.9(1.0) mK resp. This evaluation also yields the relativistic correction factor η= −(C″/C′) · Sr/R′r=1.13(2). —For the first time, too, isotope shift investigations in Sb-I lines were possible which permit to determine the isotope shift constant βCexp= 40(10) mK, and a value δ〈r2〉121, 123=0.12(4) fm2 for the change in the mean square nuclear charge radius between121Sb and123Sb which is about 50 percent of the prediction of the unified nuclear model.

Hyperfinestructure-investigations in the mangan I configurations 3d5 4s 4p and 4s 5s

Nine transitions (ranging from 475 till 733 nm) between the excited configuration 3d5 4s 5s and 3d5 4s 4p of55Mn were investigated with computer supported interference spectroscopy. Thus the hyperfine structure (hfs) of the four 4s 5s and the twelve 4s 4p levels is now completely known from experiment. The hfs results are discussed with the effective operator technique and for 4s 4p the accuracy of the one-electron parametersaik could be improved:a3d10=−6.28(24),a4s10=154.0(1.4),a4p01=9.3(8),a4p12=7.7(2.5) in mK. For the configuration 4s 5s — for which fine structure calculations are not yet available — the experimental hfs data prove a practically pureS-character. Besides the one-electron splitting parameters deduced:a3d10=−6.5(5),a4s10=182(3),a5s10=24(3) in mK, permit to determine the degree of mixing between the twoe6S5/2 andf6S5/2 levels which amounts to about 3%.

Isotope shift and hyperfine structure in the iridium I spectrum

Isotopic shift (IS) and hyperfine structure (hfs) measurements were performed in 15 lines to the ground configurations (5d+6s)9 of iridium. In a parametric description according to Bauche and Champeau accurate IS parameters were determined, and together with the IS parameters of 5 other 5d-elements, systematic trends could be noticed. The hfs analysis (with the help of the effective operator method of Sandars and Beck) yielded reliable radial integrals which permit a comparison with data from various self consistent methods. From the IS parameters and the hfs parameteras an accurate value for the nuclear parameter λ=0.044(4) fm2 could be derived.

ISOTOPE SHIFT AND HYPERFINE STRUCTURE OF STABLE PLATINUM ISOTOPES

Isotope shift (IS) and hyperfine structure (hfs) measurements have been performed on seven lines of the platinum I spectrum with interference as well as laser fluorescence spectroscopy. In the latter case a frequency-doubled single-mode cw dye laser was applied. The IS of190Pt with a natural abundance of only 0.01% was determined to beδν190, 192=−38.65(8) mK in theλ306.47 nm transition. The IS parameters and the effective hfs integrals in the configuration (5d+6s)10 were determined in intermediate coupling by a least squares fit of the IS and hfs data with eigenvectors obtained from the platinum fine structure (fs). The results are compared with theoretical values and yield improvedδ〈r2〉 data.

Analyse von Hyperfeinstrukturen des Eu151, Am241 und einiger 3 d-Elemente mittels „Exchange Polarization“

It is shown how several discrepancies in the optical hfs of the Eu can be understood as consequences of the exchange polarization of the inner and outers-electrons by the spin of the half filled (4f7)-subshell, an effect which should produce additional magnetic fields at the nucleus. Thus from the two different values of the electronic splitting constanta6s in the two Eu-II ground states the polarization field from the 6s-shell (Δ H6s) is determined to be ca. +260 KG, and the formal splitting constantσ (≃−3 mK) of the (4f7)-subshell yields ca. −350 KG for the fieldΔ H(1⋯5) from the five innern s-shells (n=1⋯5) in good agreement with the strength of the inner field obtained from recent Mössbauer effect studies.Δ H(1⋯5) is deduced to be approximately equal in all sufficiently analysed ground and excited configurations of the neutral and ionised Eu atom ((4f7) 6s, 6p, 5d, 6s2 and 6s 6p).Other elements with half filled subshells (Am, Mn) show similar features in their optical hfs. For Am+ ((5f7) 7s) ca. −2200 KG are found for the inner field (Δ H(1⋯6)).For several 3d-elements it was found that the agreement between the calculated polarization fields and those following from experimental results is better than assumed so far.

Parametric analysis of the isotope shift and hyperfinestructure in the Eu I configuration 4f7 5d 6s

With doppler-reducedintermodulatedoptogalvanicsaturation laserspectroscopy (IMOGS) in Eu I the isotope shift (IS) and hyperfine structure (hfs) of the remainingb8D term of the configuration 4f7 5d 6s was investigated. With the help of former measurements in our group (a6,10D) and by other authors (a8,10D) the IS of the now complete configuration (20 levels) was analysed with wavefunctions by J.-F. Wyart. From the parametric description of the IS resulted the necessity also to include the often neglected small parameterg1(g1(4f, 5d)=9.3(3) MHz), which is mainly due to the specific mass shift. The IS of all 20 levels can be well described by further crossed-second-order parametersg2(5d, 6s)=−401(5) MHz andg3(4f, 6s)=−27(1) MHz and one commonJ-dependent parameterz5d=40.4(4.1) MHz. — With effective one-electron parametersakl,bkl an interpretation of the magnetic and electric hfs (except for a few disturbed levels) could also be carried out.

Determination of isotope shift crossed-second-order-effects and hyperfine-structure parameters in the Eu I configuration 4f7 6s7s

In the Eu I configuration 4f7(8S)6s7s the isotope shift (IS) and hyperfine-structure (hfs) of the levelse8S7/2 andf8S7/2 were determined from the transitions 684.5 nm, 733.7 nm and 821.0 nm to 4f76s6p. Together with experimental results of our previous measurements a theoretical analysis of the IS and hfs for the complete configuration 4f7 6s7s can now be carried out.From the IS of the four 6s7s-levels we evaluated the two crossed-second-order-parametersg3(4f,6s)= −l.l(l)mK andg3(4f, 7s)= −0.1(l)mK. The ratiog3/G3 is determined for various Eu configurations and found to be equal to 5.6(3)·10−6 in complete agreement with a theoretical value following from Hartree-Fock calculations.The single electron hfs splitting constantsa10(4f)= −1.9 (3) mK,a10(6s)=396(3)mK, anda10(7s)=65(3)mK are also determined and compared with those of other Eu configurations.

The influence of the beam expanding prism in a dye laser resonator on the linewidth and its dependence on the expansion ratio

Abstract For the angular dispersion of the expanding prism in a grating tuned dye-laser resonator a correct formular (contrary to other publications) in terms of the expansion ratio M is derived: (dθ′ 1 /dλ) prism =2 M tan d n /dλ. This formula and also the extended formula for the total grating tuned dye-laser resonator are proved experimentally.

Hyperfinestructure and lifetime of the Mn I levels 3d54s4pz4P3/2,5/2 with laser-atomic-beam-spectroscopy

With laser-atomic-beam-spectroscopy the hyperfinestructure splitting constants A, B and the lifetimes τ of the Mn I levels 3d54s4p z4p3/2,5/2 were determined from the UV intercombination lines 321,7 nm and 322,5 nm. We obtained: A=−821(3)MHz, B=−40(30)MHz, τ=1120(50)nsec for the J=3/2 level and A=−607,8(1,5)MHz, B=+75(15)MHz, τ=970(50)nsec for the J=5/2 level.

J-dependence in the isotope-shift of the 4f75d6s a10D-term in the ground-configuration of Gd II

In order to extend the parametric description of the isotope shift to 5d-electrons in the lanthanides the IS of three GdII transitions (4f75d6pz10F11/2→4f75d6sa10D9/2, 11/2, 13/2) was measured with enriched isotopes and natural composition of Gd in hollow cathodes. The values −99.75(30)mK, −100.15(25)mK and −101.90(50)mK were obtained for the IS (between156Gd and160Gd) from the lines 367.1 nm, 374.4 nm and 385.6 nm resp. From theJ-dependence of the IS found in the a10D multiplet the crossed-second-order parameterz5d=1.40 (35) mK was calculated. After normalization withδ〈r2〉 andζ5d the figurez5d, norm=6.2(1.8)· 10−6 fm−2 agrees fully with the corresponding value from Eu I. This proves that theJ-dependence within a multiplet arises mainly from a crossed-second-order effect, which is originating from the field shift operator and operators of magnetic interactions.