33,805 research outputs found
Extended calculations of energy levels, radiative properties, , hyperfine interaction constants, and Land\'e -factors for nitrogen-like \mbox{Ge XXVI}
Employing two state-of-the-art methods, multiconfiguration
Dirac--Hartree--Fock and second-order many-body perturbation theory, highly
accurate calculations are performed for the lowest 272 fine-structure levels
arising from the , , , ~(), (), and ()
configurations in nitrogen-like Ge XXVI. Complete and consistent atomic data,
including excitation energies, lifetimes, wavelengths, hyperfine structures,
Land\'e -factors, and E1, E2, M1, M2 line strengths, oscillator
strengths, and transition rates among these 272 levels are provided.
Comparisons are made between the present two data sets, as well as with other
available experimental and theoretical values. The present data are accurate
enough for identification and deblending of emission lines involving the
levels, and are also useful for modeling and diagnosing fusion plasmas
S, P, D, F wave KN phase shifts in the chiral SU(3) quark model
The , , , wave phase shifts have been studied in the chiral
SU(3) quark model by solving a resonating group method equation. The numerical
results of different partial waves are in agreement with the experimental data
except for the cases of and , which are less well described
when the laboratory momentum of the kaon meson is greater than 400 MeV.Comment: Prepared for 10th International Symposium on Meson-Nucleon Physics
and the Structure of the Nucleon (MENU 2004), Beijing, China, 29 Aug - 4 Sep
200
Influence of s,p-d and s-p exchange couplings on exciton splitting in (Zn,Mn)O
This work presents results of near-band gap magnetooptical studies on
(Zn,Mn)O epitaxial layers. We observe excitonic transitions in reflectivity and
photoluminescence, that shift towards higher energies when the Mn concentration
increases and split nonlinearly under the magnetic field. Excitonic shifts are
determined by the s,p-d exchange coupling to magnetic ions, by the
electron-hole s-p exchange, and the spin-orbit interactions. A quantitative
description of the magnetoreflectivity findings indicates that the free
excitons A and B are associated with the Gamma_7 and Gamma_9 valence bands,
respectively, the order reversed as compared to wurtzite GaN. Furthermore, our
results show that the magnitude of the giant exciton splittings, specific to
dilute magnetic semiconductors, is unusual: the magnetoreflectivity data is
described by an effective exchange energy N_0(beta-alpha)=+0.2+/-0.1 eV, what
points to small and positive N_0 beta. It is shown that both the increase of
the gap with x and the small positive value of the exchange energy N_0 beta
corroborate recent theory describing the exchange splitting of the valence band
in a non-perturbative way, suitable for the case of a strong p-d hybridization.Comment: 8 pages, 8 figure
SU(5) Symmetry of spdfg Interacting Boson Model
The extended interacting boson model with s-, p-, d-, f- and g-bosons being
included (spdfg IBM) are investigated. The algebraic structure including the
generators, the Casimir operators of the groups at the SU(5) dynamical symmetry
and the branching rules of the irreducible representation reductions along the
group chain are obtained. The typical energy spectrum of the Symmetry is given.Comment: 12 pages, 2 figure
Multipole (E1, M1, E2, M2) transition wavelengths and rates between states with n<= 6 in heliumlike carbon, nitrogen, oxygen, neon, silicon, and argon
Transition wavelengths and rates are given for E1, E2, M1, and M2 transitions
between singlet and triplet S, P, D, and F states in heliumlike ions of
astrophysical interest: carbon, nitrogen, oxygen, neon, silicon, and argon. All
possible transitions between states with n <= 6 are considered. Wave functions
and energies are calculated using the relativistic configuration-interaction
(CI) method including both Coulomb and Breit interactions. For transitions to
the ground state, the present theoretical wavelengths agree to five digits with
precise measurements.Comment: 8 pages of text 97 pages of tables submitted to Atomic & Data Nuclear
Datable
Excitonic giant Zeeman effect in GaN:Mn^3+
We describe a direct observation of the excitonic giant Zeeman splitting in
(Ga,Mn)N, a wide-gap III-V diluted magnetic semiconductor. Reflectivity and
absorption spectra measured at low temperatures display the A and B excitons,
with a shift under magnetic field due to s,p-d exchange interactions. Using an
excitonic model, we determine the difference of exchange integrals between
Mn^3+ and free carriers in GaN, N_0(alpha-beta)=-1.2 +/- 0.2 eV. Assuming a
reasonable value of alpha, this implies a positive sign of beta which
corresponds to a rarely observed ferromagnetic interaction between the magnetic
ions and the holes.Comment: 4 pages, 4 figure
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