Search results for "SHELL"

Which physical parameters can be inferred from the emission variability of relativistic jets?

2005

We present results of a detailed numerical study and theoretical analysis of the dynamics of internal shocks in relativistic jets and the non-thermal flares associated with these shocks. In our model internal shocks result from collisions of density inhomogeneities (shells) in relativistic jet flows. We find that the merged shell resulting from the inelastic collision of shells has a complicated internal structure due to the non-linear dynamics of the interaction. Furthermore, the instantaneous efficiency for converting kinetic energy into thermal energy is found to be almost twice as high as theoretically expected during the period of significant emission. The Lorentz factors of the intern…

Dipole and quadrupole moments of Cu73–78 as a test of the robustness of the Z=28 shell closure near Ni78

2017

Nuclear spins and precise values of the magnetic dipole and electric quadrupole moments of the ground-states of neutron-rich $^{76-78}$Cu isotopes were measured using the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at ISOLDE, CERN. The nuclear moments of the less exotic $^{73,75}$Cu isotopes were re-measured with similar precision, yielding values that are consistent with earlier measurements. The moments of the odd-odd isotopes, and $^{78}_{29}$Cu ($N=49$) in particular, are used to investigate excitations of the assumed doubly-magic $^{78}$Ni core through comparisons with large-scale shell-model calculations. Despite the narrowing of the $Z=28$ shell gap between $N\sim45…

Translationally invariant coupled cluster method in coordinate space for nuclei

2002

We study a formulation of the translationally invariant coupled cluster method in coordinate space for finite nuclei. The new formulation remedies convergence problems that plagued previous calculations in configuration space. The method is applied to light nuclei using semi-realistic central interactions.

Nuclear Magnetic Moment ofTl207

1985

The magnetic moment 1.876(5)${\mathrm{\ensuremath{\mu}}}_{\mathit{N}}$ of 4.77-min $^{207}\mathrm{Tl}$, the only heavy nucleus with a doubly magic core plus a single ${s}_{\frac{1}{2}}$ particle or hole, was measured from the hfs by collinear fast-beam laser spectroscopy at ISOLDE (isotope separator at the CERN synchrotron). The result is of theoretical importance as a test case for core polarization since the nuclear structure is relatively simple and the orbital part of the magnetic moment, including strong pion-exchange contribution, is expected to be zero.

Sub-Barrier Coulomb Excitation ofSn110and Its Implications for theSn100Shell Closure

2007

The first excited 2(+) state of the unstable isotope Sn-110 has been studied in safe Coulomb excitation at 2.82 MeV/u using the MINIBALL array at the REX-ISOLDE post accelerator at CERN. This is the first measurement of the reduced transition probability of this state using this method for a neutron deficient Sn isotope. The strength of the approach lies in the excellent peak-to-background ratio that is achieved. The extracted reduced transition probability, B(E2 : 0(+) -> 2(+)) 0.220 +/- 0.022e(2) b(2), strengthens the observation of the evolution of the B(E2) values of neutron deficient Sn isotopes that was observed recently in intermediate-energy Coulomb excitation of Sn-108. It implies …

Communication: Spin densities within a unitary group based spin-adapted open-shell coupled-cluster theory: Analytic evaluation of isotropic hyperfine…

2015

We report analytical calculations of isotropic hyperfine-coupling constants in radicals using a spin-adapted open-shell coupled-cluster theory, namely, the unitary group based combinatoric open-shell coupled-cluster (COSCC) approach within the singles and doubles approximation. A scheme for the evaluation of the one-particle spin-density matrix required in these calculations is outlined within the spin-free formulation of the COSCC approach. In this scheme, the one-particle spin-density matrix for an open-shell state with spin S and MS = + S is expressed in terms of the one- and two-particle spin-free (charge) density matrices obtained from the Lagrangian formulation that is used for calcul…

Structure of the Odd-A, Shell-Stabilized NucleusNo102253

2005

In-beam {gamma}-ray spectroscopic measurements have been made on {sub 102}{sup 253}No. A single rotational band was identified up to a probable spin of 39/2({Dirac_h}/2{pi}), which is assigned to the 7/2{sup +}[624] Nilsson configuration. The bandhead energy and the moment of inertia provide discriminating tests of contemporary models of the heaviest nuclei. Novel methods were required to interpret the sparse data set associated with cross sections of around 50 nb. These methods included comparisons of experimental and simulated spectra, as well as testing for evidence of a rotational band in the {gamma}{gamma} matrix.

The Mean-Field Shell Model

2007

Chapter 3 introduced the notion of a nuclear mean field with associated singleparticle orbitals. It was explained how the single-particle energies can be obtained either by using an empirical Woods-Saxon potential or by the selfconsistent Hartree-Fock approach, extensively discussed in Chap. 4.

Shell-model and projected mean-field approach to electronic excitations of atomic clusters

2008

Fine structure in the beta-delayed proton decay of 33Ar

1996

9 pages, 2 figures, 2 tables.-- PACS nrs.: 21.60.Cs; 23.40.−s; 27.30.+t; 29.30.Ep.