4,526 research outputs found
Interfering Doorway States and Giant Resonances. II: Transition Strengths
The mixing of the doorway components of a giant resonance (GR) due to the
interaction via common decay channels influences significantly the distribution
of the multipole strength and the energy spectrum of the decay products of the
GR. The concept of the partial widths of a GR becomes ambiguous when the mixing
is strong. In this case, the partial widths determined in terms of the - and
-matrices must be distinguished. The photoemission turns out to be most
sensitive to the overlapping of the doorway states. At high excitation
energies, the interference between the doorway states leads to a restructuring
towards lower energies and apparent quenching of the dipole strength.Comment: 17 pages, LaTeX, 5 figures as JPEG, to appear in PRC (July 1997
Compact objects in conformal nonlinear electrodynamics
In this paper we consider a special case of vacuum non-linear electrodynamics
with a stress-energy tensor conformal to the Maxwell theory. Distinctive
features of this model are: the absence of dimensional parameter for
non-linearity description and a very simple form of the dominant energy
condition, which can be easily verified in an arbitrary pseudo-riemannian
space-time with the consequent constrains on the model parameters. In this
paper we analyse some properties of astrophysical compact objects coupled to
conformal vacuum non-linear electrodynamics
Charge transfer transitions in the photoluminescence spectra of Zn1-xMexO (Me = Mn, Ni, Co) oxide compounds
Crystals of Zn1-xCoxO and Zn1-xNixO are studied by photoluminescence at temperatures of 8 and 90 K. By resolving the spectra into sums of gaussian distributions and using the known positions of donor and acceptor levels of 3d-impurities relative to the edges of the allowed bands, the observed peaks in the photoluminescence spectra are interpreted in terms of radiative recombination through donor and acceptor levels of nickel and cobalt ions. These results are compared with previously observed features of the photoluminescence spectra of Zn1-xMnxO crystals. © 2013 American Institute of Physics
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