Influence of rotation-induced nuclear deformation on<i>α</i>-particle evaporation spectra

Huizenga, J.R.; Behkami, A.N.; Govil, I. M.; Schröder, W. U.; Tōke, J.

doi:10.1103/physrevc.40.668

Cited by 63 publications

(53 citation statements)

References 35 publications

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“…Some other authors claim that these spectra may be well explained in terms of a statistical model incorporating only a spin dependent level density and without lowering the emission barriers [10][11][12][13]. Possible deficiencies of an 'average' one step [6,7] or two step decay [12] approximation employed in some statistical model codes were pointed out, as well as the need for proper treatment of level density for expected rotating liquid drop model (RLDM) deformations [5,8,13,14].…”

Section: Introductionmentioning

confidence: 98%

“…Several papers reported that these nuclei are subjected to lower emission barriers as compared to inverse absorption channels due to large deformations at these higher excitation energy and angular momentum [2][3][4][5][6][7][8][9][10]. Some other authors claim that these spectra may be well explained in terms of a statistical model incorporating only a spin dependent level density and without lowering the emission barriers [10][11][12][13]. Possible deficiencies of an 'average' one step [6,7] or two step decay [12] approximation employed in some statistical model codes were pointed out, as well as the need for proper treatment of level density for expected rotating liquid drop model (RLDM) deformations [5,8,13,14].…”

Section: Introductionmentioning

confidence: 98%

“…Over the past decade, there have been several claims of serious discrepancies between standard statistical model predictions and measured light charged particle energy spectra [2][3][4][5][6][7][8][9][10][11][12][13]. Measured light charged particles have been characterised as having lower average energies than predicted.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Alpha particle evaporation as a probe for dynamical deformations

Govil

1999

Pramana - J Phys

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Evaporation of alpha particles in heavy ion reactions followed by fusion has proved to be a powerful probe for the properties of emitting nuclei. Detailed experimental data and different model calculations allow us to probe whether the foundation of the statistical model holds for the compound nucleus populated in these reactions. It has been observed that in the case of composite nuclei at moderate energies and angular momenta, evaporation spectra are well explained in terms of the standard statistical model CASCADE code employing optical model transmission coefficients in the description of particle evaporation. However, it has been observed that experimental particle spectra from heavy ion induced fusion reactions are no longer consistent with the predictions of such models. It has been predicted by some authors that in these systems the emission barriers are lower than those expected from optical model transmission coefficients calculated for the respective inverse absorption channels. Some authors claim that these spectra may be well explained in terms of the statistical model incorporating only spin dependent level density and without lowering the emission barriers. The field is not yet free from the controversies. Furthermore, the assumption of the very short formation time in statistical model analysis is one extreme of the general evolution process which in fact is a continuous relaxation process, leading to the composite system from the entrance channel to the equilibrated configuration. Recent dynamical description of heavy ion collisions do not support this assumption in many cases. In symmetric entrance channels and for collisions where centre of mass energy is well above the Coulomb barrier, formation time can be even larger than decay time of the resulting composite system. In such cases realistic approach will be to couple the dynamical evolution of the intrinsic excitation of the composite system to a time dependent statistical model calculation. The above question has been addressed in the light of the alpha particle spectra taken in coincidence with the evaporation residues for the asymmetric ¾ Si · ½ V and the symmetric ¾ Si · ¾ Al systems. The experimental data have been interpreted in the framework of dynamical trajectory model calculations.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 98%

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Alpha particle evaporation as a probe for dynamical deformations

Govil

1999

Pramana - J Phys

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“…Therefore if we propose the independence of α-cluster formation probability on the angle θ, then the α-particles should be emitted mainly at angle θ = 0 • (see also [23,25,30,31,32,33]). A similar effect is wellknown in the case of sub-barrier fusion reactions between spherical and deformed nuclei [34,37].…”

Section: /2mentioning

confidence: 99%

“…Therefore α-nucleus potential should depend on the angle θ between the direction of α-emission and the axial-symmetry axis of the deformed nucleus. Both the α-decay width and the transmission coefficient for tunnelling through the barrier are strongly dependent on θ [20,22,23,24,25,26,30,31,32,33]. This effect is considered in detail in microscopic models [23,24,25,26].…”

Section: Introductionmentioning

confidence: 99%

α-nucleus potential for α-decay and sub-barrier fusion

2005

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The set of parameters for α-nucleus potential is derived by using the data for both the α-decay halflives and the fusion cross-sections around the barrier for reactions α+ 40 Ca, α+ 59 Co, α+ 208 Pb. The α-decay half-lives are obtained in the framework of a cluster model using the WKB approximation. The evaluated α-decay half-lives and the fusion cross-sections agreed well with the data. Fusion reactions between α-particle and heavy nuclei can be used for both the formation of very heavy nuclei and spectroscopic studies of the formed compound nuclei.

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Deformation effects in the 28Si+12C and 28Si+28Si reactions

Bhattacharya¹,

Rousseau²,

Beck³

et al. 2001

Pramana - J Phys

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The possible occurrence of highly deformed configurations is investigated in the ¼ Ca and Ni di-nuclear systems as formed in the ¾ Si · ½¾ C, ¾ Si reactions by using the properties of emitted light charged particles. Inclusive as well as exclusive data of the heavy fragments and their associated light charged particles have been collected by using the ICARE charged particle multidetector array. The data are analysed by Monte Carlo CASCADE statistical-model calculations using a consistent set of parameters with spin-dependent level densities. Significant deformation effects at high spin are observed as well as an unexpected large Be cluster emission of a binary nature.

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Influence of rotation-induced nuclear deformation onα-particle evaporation spectra

Cited by 63 publications

References 35 publications

Alpha particle evaporation as a probe for dynamical deformations

Alpha particle evaporation as a probe for dynamical deformations

α-nucleus potential for α-decay and sub-barrier fusion

Deformation effects in the 28Si+12C and 28Si+28Si reactions

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