Isoscalar transition rates from inelastic alpha scattering

Săndulescu²,

Greiner

2002

We give a quantum description of the ternary cold fission process within a stationary scattering formalism. The dynamics of the light particle and heavy fragments is described by a self-consistent system of equations for radial wavefunctions. We consider the spontaneous cold ternary fission of 252Cf accompanied by 4He and 10Be. The light cluster decays from some resonant eigenstate in the Coulomb plus nuclear potential. It turns out that for the angular momentum projection K = 0 the light cluster emission is concentrated in the polar direction. By increasing K the maximum of the angular distribution moves towards the equator, as measured in the experiment. For 4He we predict short living decaying states. Due to a large repulsive core, proportional to K2, such states are hindered in the case of 10Be. The motion of the two heavy fragments with −K compensates the rotation of the light fragment. We call this collective motion tri-rotor mode and it should be detected in the fragment yields by magnetic transitions.

Section: Numerical Applicationmentioning

confidence: 57%

Self-consistent description of the ternary cold fission: tri-rotor mode

Săndulescu²,

Greiner

2002

“…The analysis of the α-daughter interaction is a central issue of this field. One of the most popular methods is that of the double folding procedure, presented in [48][49][50]. The double folding potential that describes the elastic scattering of α-particles was extended to nuclei of medium mass number A∼50-120 nuclei at energies from ∼13 to 50 MeV in [51].…”

Section: Interactionmentioning

confidence: 99%

Coupled channels description of theα-decay fine structure

Ren

Dumitrescu

et al. 2018

We review the coupled channels approach of α transitions to excited states. The α-decaying states are identified as narrow outgoing Gamow resonances in an α-daughter potential. The real part of the eigenvalue corresponds to the Qvalue, while the imaginary part determines the half of the total α-decay width. We first review the calculations describing transitions to rotational states treated by the rigid rotator model, in even-even, odd-mass and odd-odd nuclei. It is found that the semiclassical method overestimates the branching ratios to excited 4 + for some even-even α-emitters and fails in explaining the unexpected inversion of branching ratios of some odd-mass nuclei, while the coupled-channels results show good agreement with the experimental data. Then, we review the coupled channels method for α-transitions to 2 + vibrational and transitional states. We present the results of the Coherent State Model that describes in a unified way the spectra of vibrational, transitional and rotational nuclei. We evidence general features of the α-decay fine structure, namely the linear dependence between α-intensities and excitation energy, the linear correlation between the strength of the α-core interaction and spectroscopic factor, and the inverse correlation between the nuclear collectivity, given by electromagnetic transitions, and α-clustering.

“…We start by noticing that a realistic α-nucleus spherical potential reproducing well-scattering date is given by the double-folding procedure using the M3Y nucleon-nucleon interaction [6][7][8]. This kind of α-core potential [9][10][11] was successfully used in describing α-decays to ground [12][13][14][15] and excited states [16][17][18][19][20].…”

Section: Theoretical Backgroundmentioning

confidence: 99%

A simple approach toα-decay fine structure

Patial

Liotta

et al. 2016

We propose a simple method to evaluate α-transition rates to low-lying excited states in even-even nuclei. For this a realistic α-daughter double folding interaction is approximated by a parabola in the region where the decay process takes place. This allows us to evaluate the penetration probability analytically. The main experimental features of branching ratios to excited states are reproduced by this simple approach.