Search results for " Spheroid"
showing 10 items of 69 documents
High-spin study of neutron-deficient $^{114}$Xe
2000
Abstract High-spin states have been populated in 114 54 Xe via the 58 Ni( 58 Ni, 2p) reaction at 210 MeV, using the Jurosphere γ -ray spectrometer to record γ -ray coincidences. The known level scheme has been significantly extended and includes two positive-parity and three negative-parity structures. At the highest spins, one of the negative-parity bands becomes yrast and shows the characteristics of a smoothly terminating band. Quadrupole moments for two of the bands at high spin have been estimated through a Doppler-broadened lineshape analysis; the terminating band has a reduced quadrupole moment implying that it is not far from full termination into a noncollective oblate state. Extra…
Multi-domain spectral approach with Sommerfeld condition for the Maxwell equations
2021
We present a multidomain spectral approach with an exterior compactified domain for the Maxwell equations for monochromatic fields. The Sommerfeld radiation condition is imposed exactly at infinity being a finite point on the numerical grid. As an example, axisymmetric situations in spherical and prolate spheroidal coordinates are discussed.
Breakdown of the Reduction of the Rovibrational Hamiltonian: The Case of S18O2F2
2009
Abstract The ground state rotational spectrum of the near-spherical top molecule S18O2F2 (sulfuryl fluoride) has been measured from 50 to 700 GHz. As for the parent isotopologue, S16O2F2 [K. Sarka, J. Demaison, L. Margules, I. Merke, N. Heineking, H. Burger, H. Ruland, J. Mol. Spectrosc. 200 (2000) 55–64], it was necessary to use a non-reduced Hamiltonian in order to obtain a satisfactory fit. It was possible to determine six quartic centrifugal distortion constants (instead of five for a standard asymmetric top) and five sextic constants (one of them not existing in the reduced Hamiltonian) could also be determined. This ground state level has also been analysed thanks to a tensorial forma…
New shape isomer in the self-conjugate nucleus $^{72}$Kr
2003
A new isomeric ${0}^{+}$ state was identified as the first excited state in the self-conjugate ($N=Z$) nucleus $^{\mathrm{72}}\mathrm{K}\mathrm{r}$. By combining for the first time conversion-electron and gamma-ray spectroscopy with the production of metastable states in high-energy fragmentation, the electric-monopole decay of the new isomer to the ground state was established. The new ${0}^{+}$ state is understood as the band head of the known prolate rotational structure, which strongly supports the interpretation that $^{\mathrm{72}}\mathrm{K}\mathrm{r}$ is one of the rare nuclei having an oblate-deformed ground state. This observation gives in fact the first evidence for a shape isomer…
Collision orbits in the oblate planet problem
1984
Some of the properties of the oblate planet problem are derived. We use the technique of blowing up the singularity to study the collision orbits. We define some families of them in terms of their asymptotic behavior.
Potential and energy of some spheroidal charge distributions with azimuthal symmetry
1989
Abstract The Poisson equation is solved for three types of spheroidal charge distributions with azimuthal symmetry, namely, those depending on one cartesian coordinate, on the radial cylindrical coordinate and on the radial spherical coordinate. The energy of such distributions is found for the case of power functions of these coordinates and it has been normalized, computed and plotted for some low values of the exponent.
Transition from Prolate to Oblate to Triaxial Shapes in158Yb
1983
The decay of the entry states in ISIYb populated in the reactions of 149 MeV ,oNe with ,44Nd and lUNd has been investigated with a 4" multidetector system gated by a Ge counter. The average excitation energy, the ,.-ray spectra and the angular distribu tions as a function of multiplicity show several changes in the ,.-ray decay. These changes suggest a transition from prolate to particle aligned oblate connguration at low spin. At 1- 38-48 collective transitions with dipole and quad rupole component possibly built on high K single particle states are observed. Furthennore, above 1- 48 the dipole component disappears suggesting a further change toward more triaxial shape.
Shape coexistence in Hg-178
2019
Lifetime measurements of excited states in Hg-178 have been performed using the Rh-103(Kr-78, p2n) reaction at a beam energy of 354 MeV. The recoil-decay tagging (RDT) technique was applied to select the Hg-178 nuclei and associate the prompt gamma rays with the correlated characteristic ground-state alpha decay. Lifetimes of the four lowest yrast states of Hg-178 have been determined using the recoil distance Doppler-shift (RDDS) method. The experimental data are compared to theoretical predictions with focus on shape coexistence. The results confirm the shift of the deformed prolate structures to higher lying states but also indicate their increasing deformation with decreasing neutron nu…
Emission and null coordinates: geometrical properties and physical construction
2011
A Relativistic Positioning System is defined by four clocks (emitters) broadcasting their proper time. Then, every event reached by the signals is naturally labeled by these four times which are the emission coordinates of this event. The coordinate hypersurfaces of the emission coordinates are the future light cones based on the emitter trajectories. For this reason the emission coordinates have been also named null coordinates or light coordinates. Nevertheless, other coordinate systems used in different relativistic contexts have the own right to be named null or light coordinates. Here we analyze when one can say that a coordinate is a null coordinate and when one can say that a coordin…
Measurement of the Spin and Magnetic Moment ofMg31: Evidence for a Strongly Deformed Intruder Ground State
2005
Unambiguous values of the spin and magnetic moment of $^{31}\mathrm{M}\mathrm{g}$ are obtained by combining the results of a hyperfine-structure measurement and a $\ensuremath{\beta}$-NMR measurement, both performed with an optically polarized ion beam. With a measured nuclear $g$ factor and spin $I=1/2$, the magnetic moment $\ensuremath{\mu}(^{31}\mathrm{M}\mathrm{g})=\ensuremath{-}0.88355(15){\ensuremath{\mu}}_{N}$ is deduced. A revised level scheme of $^{31}\mathrm{M}\mathrm{g}$ ($Z=12$, $N=19$) with ground state spin/parity ${I}^{\ensuremath{\pi}}=1/{2}^{+}$ is presented, revealing the coexistence of 1p-1h and 2p-2h intruder states below 500 keV. Advanced shell-model calculations and th…