BRUSLIB - the Brussels Nuclear Library for Astrophysics

Ground State Properties

Single Particle Scheme

Density and Potential

Nuclear Level Density

Partition Function

E1 Strength Function

Fission Properties (90<=Z<=110)

Reaction Rates

last update: April. 30, 2015

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Ground State Properties

Data and Plot

Proton number Z:

Neutron number N:

Introduction

The force used in the Hartree-Fock-Bogoliubov (HFB) mass model is an extended Skyrme force (containing t₄ and t₅ terms), along with a 4-parameter delta-function pairing force derived from realistic calculations of infinite nuclear and neutron matter.
Pairing correlations are introduced in the framework of the Bogoliubov method. Deformations with axial and left-right symmetry are admitted.

The total binding energy is given by

E_tot= E_HFB+ E_wigner

where

E_HFBis the HFB binding energy including a cranking correction to the spurious rotational energy and a phenomenological vibration correction energy
E_wigner=V_w exp(-λ((N-Z)/A)²)+V_w|N-Z|exp(-(A/A₀)²) is a phenomenological correction for the Wigner energy.

The parameter set, labelled BSk24, is determined by constraining the nuclear-matter symmetry coefficient to J = 30 MeV and the isoscalar effective mass to M*_s/M = 0.8 and optimizing the fit to the full data set of the 2353 measured masses with N,Z ≥ 8 (both spherical and deformed) of Audi et al. [Chinese Physics C36, 1287 (2012)]: the corresponding root mean square error is 0.549 MeV for this data set.

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Single Particle Scheme

Data and Plot

Proton number Z:

Neutron number N:

Introduction

The total binding energy is given by

E_tot= E_HFB+ E_wigner

where

E_HFBis the HFB binding energy including a cranking correction to the spurious rotational energy and a phenomenological vibration correction energy
E_wigner=V_w exp(-λ((N-Z)/A)²)+V_w|N-Z|exp(-(A/A₀)²) is a phenomenological correction for the Wigner energy.

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Density and Potential

Data and Plot

Proton number Z:

Neutron number N:

Introduction

The total binding energy is given by

E_tot= E_HFB+ E_wigner

where

E_HFBis the HFB binding energy including a cranking correction to the spurious rotational energy and a phenomenological vibration correction energy
E_wigner=V_w exp(-λ((N-Z)/A)²)+V_w|N-Z|exp(-(A/A₀)²) is a phenomenological correction for the Wigner energy.

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Nuclear Level Density

Data and Plot

Proton number Z:

Neutron number N:

Spin number:

Introduction

The NLD predictions within the combinatorial method are based on the realistic microscopic single-particle level scheme and pairing force of the Hartree-Fock-Bogolyubov model with the BSk14 Skyrme force. The vibrational enhancement is explicitly taking into account considering phonon excitations.

More details of the nuclear level density formula can be found in

S. Hilaire, J.P. Delaroche and A.J. Koning, Nucl. Phys. A632, 417 (1998).
S. Hilaire, J.P. Delaroche and M. Girod, Eur. Phys. J. A12 (2001) 169
S. Hilaire and S. Goriely, Nucl. Phys. A779 (2006) 63
S. Hilaire and S. Goriely, In Proc. of the International Conference on Frontiers in Nuclear Structure, Astrophysics and Reactions (eds. P. Demetriou, R. Julin, S. Harissopulos, AIP Conference proceedings 1012, New York) 356-358 (2008)
S. Goriely, S. Hilaire and A.J. Koning, Phys. Rev. C78 (2008) 064307

The microscopic predictions of NLD (total, spin- and parity-dependent) for 8508 nuclei from Z=8 to 110 and lying between the proton and neutron drip lines are tabulated in an energy (U=0.25 to 200 MeV) and spin (the lowest 50 spins) grid. Also included in the tables is the the cumulative number of levels.

a zipped tar file including all nuclear level density tables can be downloaded HERE (93Mb).
(last update 17/03/2011)

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Partition Function

Data and Plot

Proton number Z:

Neutron number N:

Introduction

The partition functions are calculated using experimental excited spectrum whenever available (RIPL-3 database) and if not, on the basis of the nuclear level densities obtained within the HFB plus combinatorial method (Goriely et al., 2008, Phys. Rev. C78, 064307)

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E1 Strength Function

Data and Plot

Proton number Z:

Neutron number N:

Introduction

The E1-strength is obtained here from large-scale QRPA calulations performed on top of a Skyrme-HFB description of the ground state. The HFB+QRPA strength is obtained on the basis of the BSk7 Skyrme force [1]. The QRPA equations are solved in the configuration space so as to exhaust the energy weighted sum rule. All QRPA calculations are performed in the spherical approximation. A folding procedure is applied to the QRPA strength distribution to take the damping of the collective motion into account. In the case of deformed nuclei, a phenomenological splitting of the QRPA resonance strength is performed in the folding procedure. The resulting E1-strength function is found to be in close agreement with photo-absorption data as well as with the available experimental E1 strength at low energies. All details can be found in Ref. [2]. The HFB+QRPA strength is available for all nuclei with 8 ≤ Z ≤ 110 lying between the proton and the neutron drip lines.

[1] S. Goriely, M. Samyn, M. Bender and J.M. Pearson, Phys. Rev. C 68 (2003) 054325
[2] S. Goriely, E. Khan, and M. Samyn, Nucl. Phys. A739 (2004) 331.

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Fission Properties

Data and Plot

Proton Number Z:

Neutron Number N:

Location:

Spin:

Introduction

The present tables contain the predictions of the fission properties [1] obtained within the Hartree-Fock-Bogolyubov approach based on the BSk14 Skyrme force [2], which has proven its capacity to estimate the static fission barrier height with a relatively high degree of accuracy. In particular, the barriers determined from the present HFB-14 fission path reproduce the 52 primary empirical barriers (i.e the highest barriers) of nuclei with 88 ≤ Z ≤ 96 (which are always less than 9 MeV high) with an rms deviation as low as 0.67 MeV. A similar accuracy is obtained (0.65 MeV) for the secondary barriers.

Fission properties are provided for about 1000 nuclei with 90 ≤ Z ≤ 110 lying between the valley of beta-stability and the neutron drip line.

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Astrophysical Reaction Rates

Data and Plot

Proton number Z:

Neutron number N:

Introduction

The present estimates of thermonuclear reaction rates are obtained with the reaction code called TALYS [1,2,3]. TALYS includes many state-of-the-art nuclear models to cover all main reaction mechanisms encountered in light particle-induced nuclear reactions. TALYS provides a complete description of all reaction channels and observables and in particular takes into account all types of direct, pre-equilibrium, and compound mechanisms to estimate the total reaction probability as well as the competition between the various open channels.

The code is optimized for incident projectile energies, ranging from 1 keV up to 200 MeV on target nuclei with mass numbers between 12 and 339. It includes photon, neutron, proton, deuteron, triton, ³He, and α-particles as both projectiles and ejectiles, and single-particle as well as multi-particle emissions and fission. The TALYS code was designed to calculate total and partial cross sections, residual and isomer production cross sections, discrete and continuum γ-ray production cross sections, energy spectra, angular distributions, double-differential spectra, as well as recoil cross sections. TALYS also estimates the maxwellian-averaged reaction rates [3].

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Please refer to Yi Xu, Stephane Goriely, Alain Jorissen, Guangling Chen, Marcel Arnould, Astronomy & Astrophysics 549, A106 (2013) and the specified literatures therein when using BRUSLIB.
Any comments or suggestions please send to S. Goriely % ulb.be