Search results for "DIPOLE"
showing 10 items of 982 documents
Optical response and shapes of charged sodium clusters; an analogue of the nuclear giant dipole response
1995
Collective vibrations of de-localized electrons against the positive charged ionic background in sodium clusters (plasmon resonances) and the collective vibrations of protons against neutrons in nuclei (giant dipole resonances) have several features in common. However, fundamental differences exist due to differences in the two media; the nucleus is a quantum liquid whereas the metallic medium is more like a plasma with classical positive ions and quantized electrons. The similarities and differences are illustrated by results from optical response measurements for charged sodium clusters with 14 to 48 atoms.
Measurement of the Dipole Polarizability of the Unstable Neutron-Rich NucleusNi68
2013
The E1 strength distribution in Ni68 has been investigated using Coulomb excitation in inverse kinematics at the RB3-LAND setup and by measuring the invariant mass in the one- and two-neutron decay channels. The giant dipole resonance and a low-lying peak (pygmy dipole resonance) have been observed at 17.1(2) and 9.55(17) MeV, respectively. The measured dipole polarizability is compared to relativistic random phase approximation calculations yielding a neutron-skin thickness of 0.17(2) fm. A method and analysis applicable to neutron-rich nuclei has been developed, allowing for a precise determination of neutron skins in nuclei as a function of neutron excess.
Complete dipole response in [sup 208]Pb from high-resolution polarized proton scattering at 0°
2009
At the Research Center for Nuclear Physics, Osaka, Japan, the 208Pb(p,p´) reaction was measured at Ep=295 MeV and scattering angles Θlab= 0° - 10°. A high energy resolution of the order of ΔE/E ≈ 8x10^-5 was achieved, corresponding to ΔE=25-30 keV (FWHM). Cross sections were extracted by a multipole decomposition analysis of the angular distributions. Dominant contributions at very forward angles originate from E1 excitation due to Coulomb projectile-target interaction and spin M1 transitions caused by the spin-isospin part of the proton-nucleus interaction. A separation of these contributions was performed with two independent methods, viz. a multipole decomposition of the angular distribu…
Complete Electric Dipole Response and the Neutron Skin inPb208
2011
A benchmark experiment on Pb-208 shows that polarized proton inelastic scattering at very forward angles including 0 degrees is a powerful tool for high-resolution studies of electric dipole (E1) and spin magnetic dipole (M1) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted E1 polarizability leads to a neutron skin thickness r(skin) = 0.156(-0.021)(+0.025) fm in Pb-208 derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars.
Energy and radiative properties of the low-lying NaRb states
2001
D 1 P ‐B 1 P transition dipole moments, as well as nonadiabatic L-uncoupling matrix elements between the examined 1 P and four lowest 1 S 1 states for both 23 Na 85 Rb and 23 Na 87 Rb isotopomers. The relevant MPPT ab initio matrix elements and energy curves were converted by means of the approximate sum rule to radiative lifetimes and L-doubling constants ( q factors! for the particular rovibronic levels of the B 1 P and D 1 P states. The theoretical lifetimes agree well with their experimental counterparts for both B 1 P and D 1 P states. The q factor estimates obtained in the singlet-singlet approximation are in good agreement with the experimental ones for the D 1 P(1<v8<12;7<J8<50) lev…
Dissipation-induced stationary entanglement in dipole-dipole interacting atomic samples
2004
The dynamics of two two-level dipole-dipole interacting atoms coupled to a common electro-magnetic bath and closely located inside a lossy cavity, is reported. Initially injecting only one excitation in the two-atom cavity system, loss mechanisms asymptotically drive the matter sample toward a stationary maximally entangled state. The role played by the closeness of the two atoms, with respect to such a cooperative behavior, is carefully discussed. Stationary radiation trapping effects are found and transparently interpreted.
Finite perturbation calculation for the static dipole polarizabilities of the atoms Na through Ca
1976
Fourier-transform spectroscopy and relativistic electronic structure calculation on the c3Σ+ state of KCs
2021
Abstract The Ti:Saphire laser operated within 13800 - 11800 cm − 1 range was used to excite the c 3 Σ + state of KCs molecule directly from the ground X 1 Σ + state. The laser-induced fluorescence (LIF) spectra of the c 3 Σ + → a 3 Σ + transition were recorded with Fourier-transform spectrometer within 8000 to 10000 cm − 1 range. Overall 673 rovibronic term values belonging to both e / f -components of the c 3 Σ + ( Ω = 1 ± ) state of 39 KCs, covering vibrational levels from v = 0 to about 45, and rotational levels J ∈ [ 11 , 149 ] were determined with the accuracy of about 0.01 cm − 1 ; among them 7 values for 41 KCs. The experimental term values with v ∈ [ 0 , 22 ] were involved in a dire…
Photoluminescence structure of highly excited quantum dots of type II
2007
Abstract The photoluminescence (PL) due to decay of exciton-like e–e–h complex X– (expected to appear for higher levels of activation) in electrically defined quantum dots of type II is analyzed within the Hartree approach for Gaussian confining potential, where the existence of metastable (against far-infrared interband dipole transitions) states is predicted, due to interplay of bare confinement with Coulomb interaction between the carriers. As we will show, when three-particle complexes (e–e–h) are taken into account, three PL peaks can occur at zero magnetic field, which further split into four peaks when external magnetic field is applied, which stands in a good correspondence with the…