Isotope shifts and hyperfine structure of the BaI resonance-line (2 = 553.6 nm) have been measured by dye laser induced resonance fluorescence on an atomic beam for 135m, 129g~ 129m. 126Ba thus extending previous high resolution measurements of neutron deficient Ba nuclides (N < 82). The experimental results, now available for 16 Ba isotopes and isomers with A=14(~126, are used to deduce differences of rms charge radii, magnetic dipole and electric quadrupole moments. While the groundstates display a pronounced odd-even staggering the h 11/2 isomers 135'~Ba and 133tuBa show a decreased staggering. Conspicuously the isomer shift of the g 7/2 + isomer ~29mBa proves to be negative. The nuclear structure information is discussed in the context of gammaspectroscopic studies of transitional nuclei with 50

Isotope shifts and hyperfine structure splittings of the CaI resonance line (4s 'So-4s4p 'P~, A, =422.7 nm) have been measured for all calcium isotopes between Ca and Ca, including the short-lived isotope Ca (T~~2 --4.54 d). Resonance fluorescence was observed in a well-collimated atomic beam of calcium excited by a narrow band tunable continuous-wave dye laser. Combining the result with muonic x-ray data for the stable isotopes, accurate values for the changes of mean square charge radii of the Ca nuclei are obtained, in addition to information on electromagnetic moments from the measured hyperfine structure constants, The influence of ground state correlations (represented by quadrupole and octupole mean square deformations) on the observed peculiar variation of the Ca charge radii is discussed as well as the relation to the droplet model and to a mixed (f7/2)" model. NUCLEAR STRUCTURE Isotope shifts and hyperfine structure of Ca isotopes, 3=40 to 48, measured by laser spectroscopy, deduced 5(r ) and nuclear moments.

tate über o, das beobachtete "odd-even staggering" und die Kernmomente werden im Lichte anderer Ergebnisse über die Kernstruktur im Bereich 50 < (N,Z) < 82 diskutiert.-1 -

Te2(CF3)2 kristallisiert in der monoklinen Raumgruppe P21/a mit vier Formeleinheiten in der Elementarzelle. Die Gitterkonstanten betragen a = 10,13(1) Å, b = 11,489(7) Å, c = 6,822(8) Å und β = 101,20(8)°. Bei der Umsetzung von Te2(CF3)2 mit der äquimolaren Menge Iod entsteht CF3TeI in quantitativer Ausbeute, eine Isolierung gelingt nicht. Die NMR‐Spektren zeigen eine starke Lösungsmittelabhängigkeit. Durch Metathesereaktionen werden die Verbindungen CF3TeX (X = CCC6H5, t‐C4H9, SCN, SC6F5) synthetisiert.

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