Magnetic dipole excitation mode according to the collective model with separate neutron and proton deformations

Rohoziński, S. G.; Greiner, Walter

doi:10.1007/bf01411891

Cited by 52 publications

(28 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In fact, the fl-vibrational energies and also the energies of certain multipole giant resonances may depend very smoothly on Z and A of the giant system. This is certainly in agreement with our present understanding of nuclear structure in this exotic domain of the periodic system [28,30]. Then also the binding energy of the final state must be nearly unchanged for different combined nuclear charges Z u.…”

Section: Production Of Positron Lines By Conversion In a Giant Nucleussupporting

confidence: 80%

“…4 the K-shell conversion coefficient is displayed for nuclear transitions above the pair production threshold. To survey the dependence of c~(ls) on the nuclear charge number Z we consider as an example the nucleus Z=l14 being already outside the known periodic [28]. The total pair conversion coefficient ]~ is presented in Fig.…”

Section: Conversion Processes In Subcritical Systemsmentioning

confidence: 99%

See 1 more Smart Citation

Conversion processes in superheavy and giant atoms

Schlüter

Müller

Soff

et al. 1986

Z. Physik A - Atomic Nuclei

Self Cite

View full text Add to dashboard Cite

Conversion of bound state electrons and internal e § e--pair creation in superheavy and giant atoms are investigated. We consider various nuclear transitions of multipolarities EO, EL and ML (L> 1) in superheavy atoms with Z> 109. We are concerned in particular with the pecularities of conversion processes in supercritical systems. Our theoretical studies are confronted with the prominent peak structures observed in positron spectra of very heavy collision systems.

show abstract

Section: Production Of Positron Lines By Conversion In a Giant Nucleussupporting

confidence: 80%

Section: Conversion Processes In Subcritical Systemsmentioning

confidence: 99%

Conversion processes in superheavy and giant atoms

Schlüter

Müller

Soff

et al. 1986

Z. Physik A - Atomic Nuclei

Self Cite

View full text Add to dashboard Cite

show abstract

“…All other methods used in the study of scissors modes-the schematic random-phase approximation [5], the interacting boson model [6], the sum rule method [7], and a geometrical model [8]-give similar results.…”

mentioning

confidence: 76%

Scissors modes: The first overtone

2011

View full text Add to dashboard Cite

Scissors modes were predicted in the framework of the two-rotor model. This model has an intrinsic harmonic spectrum, so that the level above the scissors mode, the first overtone, has excitation energy twice that of the scissors mode. Because the latter is of the order of 3 MeV in the rare-earth region, the energy of the overtone is below threshold for nucleon emission, and its width should remain small enough for the overtone to be observable. We find that B(E2) ↑ overtone = The scissors mode has an excitation energy of the order of 3 MeV in the rare-earth region [1,2]. The model that led to its prediction, the two-rotor model [3], has the spectrum of a planar harmonic oscillator, with some constraints on the states to be discussed below. The first overtone should then have an energy of the order of 6 MeV, below threshold for nucleon emission. As a consequence, its width should remain of purely electromagnetic nature and be small enough for this mode to be observable, even though scissors modes have a modest collectivity and are substantially fragmented [1,2].The possible occurrence of the first overtone has been considered in Ref.[4], but to our knowledge has not been thoroughly investigated so far. The main reason is perhaps that its excitation amplitude is expected to be too small. Indeed, excitation amplitudes in the two-rotor model are proportional to powers of θ 0 , the amplitude of the zero point oscillation, which in the rare-earth region is of order 10, and the first overtone needs to be excited by an E2 multipole. All other methods used in the study of scissors modes-the schematic random-phase approximation [5], the interacting boson model [6], the sum rule method [7], and a geometrical model [10] is adopted]. This is regarded as significant evidence of the scissors nature of the low-lying magnetic transitions and their collectivity. We expect that such a proportionality should hold for the E2 strength of excitation of the first overtone as well. Even if this strength were small, its study might contribute to a deeper assessment of the nature and collectivity of the scissors modes. We then decided to start an investigation of the overtone within the two-rotor model, because this model allows a first insight into the relevant dynamics in a simple framework. We thus came to the surprising result that B(E2) ↑ overtone is of zero order in the expansion with respect to θ 0 , and, precisely,In view of the smallness of θ 0 , this amplitude is quite substantial. The above result might be relevant to some of the other electrically charged systems for which scissors modes have been predicted: metal clusters [11], quantum dots [12], and, in particular, crystals [13], for which an expansion in powers of θ 0 holds. In all these systems one of the blades of the scissors must be identified with a moving cloud of particles (electrons in metal clusters and quantum dots, an atom in a cell in crystals) and the other one with a structure at rest, the lattice. To make this Rapid Communication self-contained we report the...

show abstract

“…For a given ~, the states with the same principal quantum number N = nx_}_ i i ny + n~ (6) form a major shell for the z system. As in [22], we restrict the single particle (s.p.)…”

Section: H~p-2m /~ +~-(Co~mentioning

confidence: 99%

Toward a microscopic description of theM1 states in deformed even-odd nuclei

Râduţâ

Indice

1989

Z. Physik A - Atomic Nuclei

View full text Add to dashboard Cite

The magnetic dipole collective excitation, known as scissors mode, is studied in odd deformed nuclei within the framework of a particle-core coupling scheme. The description is made in the intrinsic and laboratory frames. In both frames the core is described in the RPA approach by a schematic many body Hamiltonian. In the intrinsic frame we use an effective particle-core Hamiltonian which is treated perturbatively. In the laboratory frame two K = 1/2 triplets with J = 1/2, 3/2, 5/2 are constructed through projection from two intrinsic excited states respectively. Each member of these multiplets are collectively M1 excited from the state (K, J~)=(3/2, 3/2+). Their energies are obtained by averaging a rotationally invariant Hamiltonian. Another multiplet with K = 3/2 and J=3/2, 5/2, which is strongly coupled to the state (K, J~)=(5/2, 5/2 +) through a M1 transition, is described. These results indicate that the M1 collective excitation should exist also in odd deformed nuclei.

show abstract

Magnetic dipole excitation mode according to the collective model with separate neutron and proton deformations

Cited by 52 publications

References 29 publications

Conversion processes in superheavy and giant atoms

Conversion processes in superheavy and giant atoms

Scissors modes: The first overtone

Toward a microscopic description of theM1 states in deformed even-odd nuclei

Contact Info

Product

Resources

About