Entrance channels and alpha decay half-lives of the heaviest elements

Royer, G.; Zbiri, K.; Bonilla, C.

doi:10.1016/j.nuclphysa.2003.11.010

Cited by 60 publications

(33 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The half-lives resulting from [51] are systematically overestimated as a consequence of the underestimated Q α -values. (The Viola-Seaborg-type formula from [50] has been used to convert Q α to half-lives). In all three discussed chains, our results are slightly overestimated.…”

Section: Resultsmentioning

confidence: 99%

Qαvalues in superheavy nuclei from the deformed Woods-Saxon model

2014

View full text Add to dashboard Cite

Masses of superheavy (SH) nuclei with Z = 98−128, including odd and odd-odd nuclei, are systematically calculated within the microscopic-macroscopic model based on the deformed Woods-Saxon potential. Ground states are found by minimizing energy over deformations and configurations. Pairing in odd particle-number systems is treated either by blocking or by adding the BCS energy of the odd quasiparticle. Three new parameters are introduced which may be interpreted as the constant mean pairing energies for even-odd, odd-even and odd-odd nuclei. They are adjusted by a fit to masses of heavy nuclei. Other parameters of the model, fixed previously by fitting masses of even-even heavy nuclei, are kept unchanged. With this adjustment, the masses of SH nuclei are predicted and then used to calculate α-decay energies to be compared to known measured values. It turns out that the agreement between calculated Qα values with data in SH nuclei is better than in the region of the mass fit. The model overestimates Qα for Z = 111 − 113. Ground state (g.s.) configurations in some SH nuclei hint to a possible α-decay hindrance. The calculated configurationpreserving transition energies show that in some cases this might explain discrepancies, but more data is needed to explain the situation.

show abstract

Section: Resultsmentioning

confidence: 99%

Qαvalues in superheavy nuclei from the deformed Woods-Saxon model

2014

View full text Add to dashboard Cite

show abstract

“…The accuracy of the generalized liquid drop model, GLDM, of Royer et al [14][15][16][17] towards the prediction of alpha half-lives, has been tested in a detailed manner. The analytical formula of [14] was modified resulting in the DSR-E formula that has the advantage of possessing coefficients derived from a reliable data base (REFERENCE).…”

Section: Resultsmentioning

confidence: 99%

“…Recently Royer et al [14][15][16][17] have described the potential barrier in alpha decay in terms of a quasi-molecular shape path within a Generalized Liquid Drop Model (GLDM)…”

Section: The Generalized Liquid Drop Model Formula For Alpha Decay Hamentioning

confidence: 99%

The generalized liquid drop model alpha-decay formula: Predictability analysis and superheavy element alpha half-lives

Dasgupta‐Schubert

Reyes²

2007

Atomic Data and Nuclear Data Tables

View full text Add to dashboard Cite

The predictive accuracy of the generalized liquid drop model (GLDM) formula for alpha decay half-lives has been investigated in a detailed manner and a variant of the formula with improved coefficients is proposed. The method employs the experimental alpha half-lives of the well-known alpha standards (REFERENCE) to obtain the coefficients of the analytical formula using the experimental Q α values (the DSR-E formula), as well as the finite range droplet model (FRDM) derived Q α values (the FRDM-FRDM formula). The predictive accuracy of these formulae were checked against the experimental alpha half-lives of an independent set of nuclei (TEST) that span approximately the same Z,A region as the standards and possess reliable alpha spectroscopic data, and were found to yield good results for the DSR-E formula but not for the FRDM-FRDM formula. The two formulae were used to obtain the alpha half-lives of super-heavy (SHE) and heavy nuclides where the relative accuracy was found to markedly improve for the FRDM-FRDM, which corroborates the appropriateness of the FRDM masses and the GLDM prescription for high Z,A nuclides. Further improvement resulted, especially for the FRDM-FRDM formula, after a simple linear optimization over the calculated and experimental half-lives of TEST was used to re-calculate the half-lives of the SHE and heavy nuclides. The advantage of this optimization was that it required no recalculation of the coefficients of the basic DSR-E or FRDM-FRDM formulae. The halflives for 324 medium-mass to super-heavy alpha decaying nuclides, calculated using these formulae and the comparison with experimental half-lives, are presented. Often the main and sometimes the only decay mode of these nuclei is alpha decay.For the SHE, the product nuclides of hot-fusion heavy ion reactions closest to the shell model predicted Island of Stability, decay by the emission of alpha particles. Chains of successive alpha decays are terminated by spontaneous fission as the shell-stabilized region is left behind [5,2].Thus identifying and characterizing the alpha decay sequences form a crucial part of the identification of SHE. Theoretically the mechanism is described by quantum mechanical tunneling through the potential energy barrier leading from the mother nucleus to the daughter nucleus and alpha particle. Consequently the predicted half-lives remain very sensitive to the shape and energetics of the barrier which as such, serve to test the particular theoretical model of the potential energy surfaces of these exotic nuclei. Various theoretical prescriptions since 1930 [6] have been proposed. Some of these as well as some empirical observations have been reduced to analytical formulae [7][8][9][10][11][12] that connect Q α , and the Z,A of the parent nuclide and wherein coefficients are typically obtained from fits to known alpha half-lives. The underlying model's description of the potential barrier lies implicit in the formula's functional form and its coefficients and this in part determines the merit of the formula....

show abstract

“…The GLDM allows to describe the processes of fusion, fission, light nucleus and α emission [9,10,11,12,13,14,15,16,17]. The macroscopic energy includes the volume, surface, Coulomb and proximity energies:…”

Section: Methodsmentioning

confidence: 99%

Proton radioactivity within a generalized liquid drop model

2009

Self Cite

View full text Add to dashboard Cite

The proton radioactivity half-lives of spherical proton emitters are investigated theoretically. The potential barriers preventing the emission of proton are determined in the quasimolecular shape path within a generalized liquid drop model (GLDM) including the proximity effects between nuclei in a neck and the mass and charge asymmetry. The penetrability is calculated in the WKB approximation. The spectroscopic factor has been taken into account in half-life calculation, which is obtained by employing the relativistic mean field (RMF) theory combined with the BCS method with the force NL3. The half-lives within the GLDM are compared with the experimental data and other theoretical values. GLDM works quite well for spherical proton emitters when the spectroscopic factors are considered, indicating the necessity of introducing the spectroscopic factor and the success of the GLDM for proton emission. Finally, we present two formulae for proton emission half-life similar to the Viola-Seaborg formulae and Royer's formulae of α-decay.

show abstract

Entrance channels and alpha decay half-lives of the heaviest elements

Cited by 60 publications

References 24 publications

Qαvalues in superheavy nuclei from the deformed Woods-Saxon model

Qαvalues in superheavy nuclei from the deformed Woods-Saxon model

The generalized liquid drop model alpha-decay formula: Predictability analysis and superheavy element alpha half-lives

Proton radioactivity within a generalized liquid drop model

Contact Info

Product

Resources

About