Alpha widths in deformed nuclei: Microscopic approach (original) (raw)

Alpha decay from deformed nuclei

Nuclear Physics A, 1987

The reaction-theoretical formulation of (Y decay theory is extended to deformed nuclei in a particle-plus-rotor model and adapted for the use of harmonic oscillator functions. For testing purposes the formalism is applied to the decay of nuclides with reasonably well-established ground state shapes (spherical as well as deformed).

Effect of nuclear deformation on α-decay half-lives

Physical Review C, 2012

We systematically investigate the influence of nuclear deformations on the alpha-decay half-lives of the deformed medium, heavy and superheavy nuclei for 106 ≤ A ≤ 273 and 52 ≤ Z ≤ 110 from the ground state to ground state alpha transitions within the framework of the WKB method by considering the Bohr-Sommerfeld quantization condition. The deformed Wood-Saxon form in a phenomenological way and the deformed Coulomb potential in a special form have been used in order to take into account all deformation effects in the calculations and the preformation of the parent nuclei have also been regarded. Calculations have been conducted for the spherical nuclei in order to present clearly the effects of the deformations on the half-lives. We point out that all considerations have improved the results and very good agreement has been obtained with experimental data.

Penetration factor in deformed potentials: Application to α decay with deformed nuclei

A new averaging process of the calculation of α-decay half-lives for heavy and superheavy nuclei is studied in the framework of a deformed density-dependent cluster model. The potential between a spherical α particle and a deformed daughter nucleus is calculated numerically from the double-folding model by the multipole expansion method. The nuclear potential is calculated at each α-particle emission angle applying the Bohr-Sommerfeld condition at each case. The penetration factors and the half-lives for all the emission angles are evaluated with the new averaging process and compared with older values based on a fixed value of the nuclear potential depth. Finally, the half-lives of 83 even-even heavy nuclei in the atomic-number range 82-118 are calculated by the two methods and compared with their experimental values and the corresponding half-lives of the spherical daughter nuclei.

Α-Decay Spectroscopy of Deformed Nuclei Reexamined

Physical Review C, 2008

We perform an extensive analysis of α-decays to 2 + and 4 + states in deformed even-even nuclei by using the stationary coupled channels approach. Collective excitations are described within the rigid rotor model. The α-nucleus interaction is given by a double folding procedure with M3Y plus Coulomb nucleon-nucleon forces. We use a repulsive potential with one independent parameter in order to localize the α-particle on the nuclear surface and to fit the experimental Q-value. The decaying state is identified with the first resonance inside the resulting pocket-like potential, as suggested by microscopic calculations. We obtain a good agreement with existing experimental data concerning decay widths to J = 2 + , 4 + states. The total α-decay half-lives agrees very well with experimental values by fitting the spectroscopic factor in terms of charge and neutron numbers separately for Z < 82 and Z > 82. We give predictions for intensities and hindrance factors for 52 even-even α-emitters with β 2 > 0.15 and E 2 + < 200 kev. Comparison between the phenomenological and microscopic spectroscopic factors revealed large α-clustering components for nuclei close and above N = 82, Z = 82, N = 126 magic numbers.

Microscopic description of the anisotropy in alpha decay

Physical Review C, 1994

A microscopic description of alpha decay of odd mass nuclei is given for axially deformed nuclei. Realistic mean field+pairing residual interaction in a very large single particle basis is used. Systematics for At and Rn isotopes, as well as for Fr, are given. A pronounced anisotropic emission of alpha particles at low temperatures is predicted as function of deformation for the At and Rn isotopes. This shows that alpha decay is an excellent tool to probe intrinsic deformations in nuclei.

Anisotropy in alpha decay of odd-mass deformed nuclei

Physical Review C, 1992

Angular distributions and the corresponding absolute a decay widths are calculated microscopically in odd axially deformed nuclei. It is found that the angular distributions are mainly determined by the deformation. The available experimental data are well reproduced.

Signatures of nuclear deformation in beta decay patterns

Progress in Particle and Nuclear Physics, 2006

The influence of the nuclear shape on Gamow-Teller strength distributions is considered here for the case of neutron-deficient lead isotopes with even mass number from 184 to 194. Our theoretical framework is based on a deformed Hartree-Fock (HF) mean field with pairing interactions within Bardeen-Cooper-Schrieffer approximation (BCS). Residual spin-isospin interactions in the particle-hole and particle-particle channels are also included within quasiparticle random phase approximation (QRPA). After considering the sensitivity of the Gamow-Teller (GT) strength distributions to the various ingredients in the formalism, we conclude that the β + -decay patterns of these isotopes show specific signatures for each nuclear shape.

Relation of α-Decay Rotational Signatures to Nuclear Deformation Changes

Physical Review Letters, 1978

ABSTRACT It is shown that the rotational signatures for ground-band a decay can be calculated from nuclear (32 and (3 4 deformation values. The a-decay probability function over the nuclear surface is equated with the differences of the parent and daughter surfaces, hence with the changes in deformation parameters. It is suggested that deformation val­ues can be used to infer a wave functions at the nuclear surface for. a -transfer reaction theory on rotational signatures.