14 research outputs found
Delta I = 1 staggering in octupole bands of light actinides: "Beat" patterns
The Delta I = 1 staggering (odd--even staggering) in octupole bands of light
actinides is found to exhibit a ``beat'' behaviour as a function of the angular
momentum I, forcing us to revise the traditional belief that this staggering
decreases gradually to zero and then remains at this zero value. Various
algebraic models (spf-Interacting Boson Model, spdf-IBM, Vector Boson Model,
Nuclear Vibron Model) are shown to predict in their su(3) limits constant
staggering for this case, being thus unable to describe the ``beat'' behaviour.
An explanation of the ``beat'' behaviour is given in terms of two Dunham
expansions (expansions in terms of powers of I(I+1)) with slightly different
sets of coefficients for the ground state band and the negative parity band,
the difference in the values of the coefficients being attributed to Coriolis
couplings to other negative parity bands. Similar ``beat'' patterns have
already been seen in rotational bands of some diatomic molecules, like AgH.Comment: LaTeX, 17 pages plus 14 figures given in separate .ps file
The 3-Dimensional q-Deformed Harmonic Oscillator and Magic Numbers of Alkali Metal Clusters
Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator
with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal
clusters, as well as to theoretical predictions of jellium models, Woods--Saxon
and wine bottle potentials, and to the classification scheme using the 3n+l
pseudo quantum number. The 3-dimensional q-deformed harmonic oscillator
correctly predicts all experimentally observed magic numbers up to 1500 (which
is the expected limit of validity for theories based on the filling of
electronic shells), thus indicating that Uq(3), which is a nonlinear extension
of the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic
oscillator, is a good candidate for being the symmetry of systems of alkali
metal clusters.Comment: 13 pages, LaTe
Unified description of magic numbers of metal clusters in terms of the 3-dimensional q-deformed harmonic oscillator
Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator
with Uq(3)>SOq(3) symmetry are compared to experimental data for atomic
clusters of alkali metals (Li, Na, K, Rb, Cs), noble metals (Cu, Ag, Au),
divalent metals (Zn, Cd), and trivalent metals (Al, In), as well as to
theoretical predictions of jellium models, Woods-Saxon and wine bottle
potentials, and to the classification scheme using the 3n+l pseudo quantum
number. In alkali metal clusters and noble metal clusters the 3-dimensional
q-deformed harmonic oscillator correctly predicts all experimentally observed
magic numbers up to 1500 (which is the expected limit of validity for theories
based on the filling of electronic shells), while in addition it gives
satisfactory results for the magic numbers of clusters of divalent metals and
trivalent metals, thus indicating that Uq(3), which is a nonlinear extension of
the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic
oscillator, is a good candidate for being the symmetry of systems of several
metal clusters. The Taylor expansions of angular momentum dependent potentials
approximately producing the same spectrum as the 3-dimensional q-deformed
harmonic oscillator are found to be similar to the Taylor expansions of the
symmetrized Woods-Saxon and wine-bottle symmetrized Woods-Saxon potentials,
which are known to provide successful fits of the Ekardt potentials.Comment: 23 pages including 7 table
Delta I = 2 staggering in rotational bands of diatomic molecules as a manifestation of interband interactions
It is shown that the recently observed Delta I = 2 staggering seen in
superdeformed nuclear bands is also occurring in certain electronically excited
rotational bands of diatomic molecules. In the case of diatomic molecules the
effect is attributed to interband interactions (bandcrossings).Comment: LaTeX, 9 pages plus 24 figures given in separate .ps file