Inelastic electron scattering from fluctuations in the nuclear charge distribution

The information at present available concerning isotope effects in the nuclear charge distribution in the ground state for the abundant isotopes of tin is discussed. Recent spectroscopic data are included, leading to new results for the changes in mean square radius δ < r 2 > over this range of nuclei; 116–117, 0.049; 116–118, 0.124; 118–119, 0.044; 118–120, 0.112; 120–122, 0.101; 122–124, 0.091 (all in square femtometres). The error in all cases is estimated to be ± 7%. These values are on average less than half those calculated assuming incompressible nuclear matter, and for the even isotopes decrease regularly with mass number. A comparison of electronic and muonic isotope shift measurements in terms of a two-parameter Fermi distribution of nuclear charge shows that the smallness of δ ( r 2 ) may be due to changes occurring in the surface region of the nucleus, the nucleon density in the central region remaining approximately constant. This result is consistent with data from electron scattering experiments. The contributions to δ ( r 2 ) due to changes in nuclear deformation are evaluated.

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Isotope shifts in medium-heavy elements

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1967.0003 ◽

1967 ◽

Vol 296 (1444) ◽

pp. 24-37 ◽

Cited By ~ 9

Keyword(s):

Charge Distribution ◽

Electron Scattering ◽

Coulomb Excitation ◽

Nuclear Charge ◽

Nuclear Volume ◽

Heavy Elements ◽

Scattering Data ◽

Isotope Shifts ◽

Nuclear Charge Distribution ◽

Quantitative Treatment

Isotope shifts in the atomic spectra of elements covering the range between the magic neutron numbers 50 and 82 are discussed in terms of nuclear charge distribution. A comparison with evidence obtained from Coulomb excitation experiments shows that for some elements, the variation of field shifts within the sequences of even-even isotopes cannot be due solely to deformation effects, whether static or vibrational. A quantitative treatment shows that the increase of nuclear volume, or the change of nuclear charge distribution due to purely radial, as distinct from deformation, effects, occurs in markedly unequal steps as neutron pairs are added. The evidence is particularly striking in Sn and Cd, where deformations are small, and vary little among the even isotopes. Values of radial changes are obtained from the isotope shift results and com pared with the values predicted from electron scattering data. It also appears that the odd-even staggering cannot always be attributed to deformation effects.

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Isotope effects in the nuclear charge distribution in zinc

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1982.0155 ◽

1982 ◽

Vol 384 (1786) ◽

pp. 205-216 ◽

Cited By ~ 9

Keyword(s):

Charge Distribution ◽

Electron Scattering ◽

Coulomb Excitation ◽

Nuclear Charge ◽

Isotope Effects ◽

Light Element ◽

Optical Measurements ◽

Isotope Shifts ◽

Nuclear Charge Distribution ◽

The Mean

Recently reported measurements of optical isotope shifts in zinc for isotopes with mass numbers 64, 66, 67, 68 and 70 are interpreted in terms of variations in the nuclear charge distribution. The shifts, which were measured in the transition 3d 10 4p 2 P ½ -3d 9 4s 2 2 D 3/2 of Zn II at 589.4 nm, are separated into field and mass contributions. The relative field shifts are as follows: 66, 64; 1.0, 68, 66; 0.84 +0.04 -0.06 , 70, 68; 0.97 +0.06 -0.04 . 67, 66; 0.19 +0.09 -0.13 . These are proportional to the corresponding differences δ< r 2 > in the mean square nuclear charge radii. Results of electron scattering, muonic isotope shift and Coulomb excitation experiments are discussed with reference to the optical measurements. It is shown that even for this light element muonic isotope shifts are not proportional to δ< r 2 ) within the experimental error, and that nuclear deformation may be responsible for this. The measurements on 67 Zn suggest that this nucleus has static and dynamic contributions to its deformation.

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