Mean square charge radii

In the optical spectroscopy experiments, data on the isotope shifts (IS) may be obtained in addition to those on the hfs. The important nuclear information on the changes of mean square charge radii, deduced from the IS results, will be discussed by Kluge at this symposium [KLU85]. 

Prior to about 1955 much of the nuclear information was obtained from application of atomic physics. The nuclear spin, nuclear magnetic and electric moments and changes in mean-squared charge radii are derived from measurement of the atomic hyperfine structure (hfs) and Isotope Shift (IS) and are obtained in a nuclear model independent way. With the development of the tunable dye laser and its use with the online isotope separator this field has been rejuvenated. The scheme of collinear laser/fast-beam spectroscopy [KAU76] promised to be useful for a wide variety of elements, thus UNISOR began in 1980 to develop this type of facility. The present paper describes some of the first results from the UNISOR laser facility. 

ISOLDE facility at CERN [EBE85a]. Systematical data on magnetic dipole moments, electric quadrupole moments and isotope shifts were obtained in the mass range A=105 to A=127. The mean square charge-radii, deduced from measured isotope shifts, show clearly onset and disappearance of deformation, if compared to a simple two-parameter formula (see Fig.2). The lat-... 

Fig. 2. Change of the nuclear mean square charge radii 6 for indium and... 

Here, I will not discuss the hyperfine anomaly nor the additional important nuclear information on changes of mean square charge radii obtained from isotope shift (IS) data in optical experiments. 

Mean Square Charge Radii and Nuclear Shape... 

Figure 15. Change of the mean square charge radii 8 r ) in the isotopic chain as a...

Figure 16. Differences in the nuclear mean square charge radii between even isotopes of neutron numbers N -2 and N (Brix-Kopfermann diagram) for the rare-earth region. The curve for Dy is similar to those for Nd, Sm, and Gd which also show the peak from the sudden onset of deformation at N - 90. This effect disppears in the lighter and heavier elements. Data points above (below) the dashed droplet model line indicate increasing (decreasing) deformation from N-2 to N, and the reversal of this effect is due to the N = 82 shell closure.

Figure 17. Differences of mean square charge radii and odd-even staggering in Ra. The upper curve corresponds to the plot of Figure 16. The lower curve represents the changes between neighboring isotopes with solid dots (open circles) for the steps from odd to even (even to odd) neutron number.

In this way the specific mass shifts and the changes in the mean square charge radii are eliminated. However, only relative changes in... 

H. Gerhardt, E. Matthias, H. Rinneberg, F. Schneider, A. Tim-mermann, R. Wenz, P.J. West, Changes in Nuclear Mean Square Charge Radii of Stable Krypton Isotopes, Z. Phys. A292 7... 

H. L. Ravn, J.B. McGrory, Differences of the Mean Square Charge Radii of the Stable Lead Isotopes Observed through Electronic K X-Ray Shifts, submitted to Nuovo Cimento (1982). 

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