Search results for "Charge Density"
showing 10 items of 206 documents
Nuclear Charge Radii ofMg21−32
2012
Charge radii of all magnesium isotopes in the sd shell have been measured, revealing evolution of the nuclear shape throughout two prominent regions of assumed deformation centered on (24)Mg and (32)Mg. A striking correspondence is found between the nuclear charge radius and the neutron shell structure. The importance of cluster configurations towards N=8 and collectivity near N=20 is discussed in the framework of the fermionic molecular dynamics model. These essential results have been made possible by the first application of laser-induced nuclear orientation for isotope shift measurements.
Imaging Static Charge Distributions: A Comprehensive KPFM Theory
2018
We analyze Kelvin probe force microscopy (KPFM) for tip-sample systems that contain static charges by presenting a rigorous derivation for the respective KPFM signal in all common KPFM modes, namely amplitude modulation, frequency modulation, or heterodyne detection in the static, open-loop or closed-loop variant. The electrostatic model employed in the derivation is based on a general electrostatic analysis of an arbitrary tip-sample geometry formed by two metals, and which can include a static charge distribution and dielectric material in-between. The effect of the electrostatic force on the oscillating tip is calculated from this model within the harmonic approximation, and the observab…
Isotope shifts and nuclear-charge radii in singly ionizedCa40–48
1992
The isotope shifts in the resonance lines 4${\mathit{s}}_{1/2}$\ensuremath{\rightarrow}4${\mathit{p}}_{1/2,3/2}$ in Ca ii have been measured for the isotopes $^{40\mathrm{\ensuremath{-}}48}\mathrm{Ca}$ by fast-ion-beam collinear laser spectroscopy. Atomic many-body perturbation theory was then used to calculate the electronic factor for the field shift, giving F=-285(3) MHz/${\mathrm{fm}}^{2}$. The estimate of the uncertainty in F is based on the agreement at the level of 1% for the 4s and 4p hyperfine structures obtained using the same wave functions which include core polarization and pair correlation to all orders. The theoretical value is in excellent agreement with the result F=-283(6)…
Collinear Resonance Ionization Spectroscopy of Neutron-Deficient Francium Isotopes
2013
The magnetic moments and isotope shifts of the neutron-deficient francium isotopes 202-205Fr were measured at ISOLDE-CERN with use of collinear resonance ionization spectroscopy. A production-to-detection efficiency of 1% was measured for 202Fr. The background from nonresonant and collisional ionization was maintained below one ion in 105 beam particles. Through a comparison of the measured charge radii with predictions from the spherical droplet model, it is concluded that the ground-state wave function remains spherical down to 205Fr, with a departure observed in 203Fr (N = 116). ispartof: Physical Review Letters vol:111 issue:21 pages:212501-4 ispartof: location:United States status: pub…
Measuring the surface thickness of the weak charge density of nuclei
2020
The present PREX-II and CREX experiments are measuring the rms radius of the weak charge density of $^{208}$Pb and $^{48}$Ca. We discuss the feasibility of a new parity violating electron scattering experiment to measure the surface thickness of the weak charge density of a heavy nucleus. Once PREX-II and CREX have constrained weak radii, an additional parity violating measurement at a momentum transfer near 0.76 fm$^{-1}$ for $^{208}$Pb or 1.28 fm$^{-1}$ for $^{48}$Ca can determine the surface thickness.
THE STRUCTURE OF THE NUCLEONS
1980
Electron-proton and electron-deuteron scattering experiments in a wide four momentum range provide information about the structure of the proton and the neutron. The structure is a direct consequence of the hadronic interaction of the nucleon and reveals properties of the strong interaction. Absolute differential cross sections can be expressed in terms of electromagnetic form factors which lead to an understanding of the coupling mechanism between the electromagnetic field and the strongly interacting hadron. The structure can also be discussed in terms of charge densities, but this analysis is strongly restricted by recoil effects. The charge rms radius extracted from recent measurements …
Ground state correlations and the nuclear charge distribution
1979
Combining a sum rule approach and the generator coordinate model we evaluate the influence of ground state correlations on the moments of the radial charge distribution. The isotopic and isotonic differences of the moments come out to be particularly sensitive to fluctuations of the ground state correlations due to changes in the low energy spectrum. A comparison with the experimental results for the isotopes of Ca, Fe, Ni and Zn shows a fair agreement and confirms the importance of the ground state correlations for isotopic and isotonic differences of radial moments.
Behavior of the nuclear charge radii systematics in thes-dshell from muonic atom measurements
1992
The present work extends the systematics of nuclear charge radii obtained by the method of muonic atoms to nuclei with 8\ensuremath{\le}Z,N\ensuremath{\le}20. The accuracy of the measured muonic Lyman transition energies of generally \ensuremath{\le}10 eV leads to a precision in the model-independent nuclear charge radii differences of 2--3 am for the isotope shifts and 4--9 am for isotone shifts. Both isotope and isotone shifts within the s-d shell behave ``anomalously'' with respect to the systematics of heavier nuclei. However, such behavior is predicted on theoretical grounds, if mixing in the s-d shells and the strong deformation of some of the nuclei in this region are considered. We …
Charge radii and ground state structure of lithium isotopes: Experiment and theory reexamined
2011
Changes in the nuclear charge radii of lithium isotopes were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. We discuss the choice of the reference isotope for absolute charge radii determinations in the lithium isotopic chain and report a new value for the charge radius of ${}^{6}$Li, based on the analysis of the world scattering data. A summary of the lithium nuclear charge radii obtained in this way is presented. Additionally, new calculations in fermionic molecular dynamics for the lithium isotopes were performed. We summarize the status of the lithium nuclear charge radii, magnetic dipole and electric quadrupole moment…
Charge-radius change and nuclear moments in the heavy tin isotopes from laser spectroscopy: Charge radius ofSn132
2005
Laser spectroscopy measurements have been carried out on the neutron-rich tin isotopes with the COMPLIS experimental setup. Using the $5{s}^{2}5{p}^{2\phantom{\rule{0.3em}{0ex}}3}{P}_{0}\ensuremath{\rightarrow}5{s}^{2}5p6s\phantom{\rule{0.3em}{0ex}}{}^{3}{P}_{1}$ optical transition, hyperfine spectra of $^{126\ensuremath{-}132}\mathrm{Sn}$ and $^{125,127,129\ensuremath{-}131}\mathrm{Sn}{}^{m}$ were recorded for the first time. The nuclear moments and the mean square charge radius variation ($\ensuremath{\delta}\ensuremath{\langle}{r}_{c}^{2}\ensuremath{\rangle}$) were extracted. From the quadrupole moment values, these nuclei appear to be spherical. The magnetic moments measured are thus co…