58,356 research outputs found
Electromagnetic quasinormal modes of D-dimensional black holes II
By using the sixth order WKB approximation we calculate for an
electromagnetic field propagating in D-dimensional Schwarzschild and
Schwarzschild de Sitter black holes its quasinormal frequencies for the
fundamental mode and first overtones. We study the dependence of these QN
frequencies on the value of the cosmological constant and the spacetime
dimension. We also compare with the known results for the gravitational
perturbations propagating in the same background. Moreover we exactly compute
the QN frequencies of the electromagnetic field propagating in D-dimensional
massless topological black hole and for charged D-dimensional Nariai spacetime
we exactly calculate the QN frequencies of the coupled electromagnetic and
gravitational perturbations.Comment: 34 pages, 14 figures, 6 table
One-dimensional relativistic dissipative system with constant force and its quantization
For a relativistic particle under a constant force and a linear velocity
dissipation force, a constant of motion is found. Problems are shown for
getting the Hamiltoninan of this system. Thus, the quantization of this system
is carried out through the constant of motion and using the quantization of the
velocity variable. The dissipative relativistic quantum bouncer is outlined
within this quantization approach.Comment: 11 pages, no figure
Structures and Stabilities of Doubly-charged (MgO)nMg2+ (n=1-29) Cluster Ions
Ab initio perturbed ion plus polarization calculations are reported for
doubly-charged nonstoichiometric (MgO)nMg2+ (n=1-29) cluster ions. We consider
a large number of isomers with full relaxations of the geometries, and add the
correlation correction to the Hartree-Fock energies for all cluster sizes. The
polarization contribution is included at a semiempirical level also for all
cluster sizes. Comparison is made with theoretical results for neutral (MgO)n
clusters and singly-charged alkali-halide cluster ions. Our method is also
compared to phenomenological pair potential models in order to asses their
reliability for calculations on small ionic systems. The large
coordination-dependent polarizabilities of oxide anions favor the formation of
surface sites, and thus bulklike structures begin to dominate only after n=24.
The relative stabilities of the cluster ions against evaporation of a MgO
molecule show variations that are in excellent agreement with the experimental
abundance spectra.Comment: Final version accepted in Journal of Chemical Physics; 8 pages plus 8
figures (6 GIFs and 2 PSs). The main difference with respect to the original
submission is the inclusion of coordination-dependent polarizabilities for
oxide anions. That results in substantial changes in the result
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