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We use the auxiliary-fields Monte Carlo method for the shell model in the complete $(pf+0g_{9/2})$-shell to calculate level densities. We introduce parity projection techniques which enable us to calculate the parity dependence of the level…

Nuclear Theory · Physics 2009-10-30 H. Nakada , Y. Alhassid

Nuclear level densities are crucial for estimating statistical nuclear reaction rates. The shell model Monte Carlo method is a powerful approach for microscopic calculation of state densities in very large model spaces. However, these state…

Nuclear Theory · Physics 2013-04-29 Y. Alhassid , M. Bonett-Matiz , S. Liu , H. Nakada

The prediction of cross sections for nuclei far off stability is crucial in the field of nuclear astrophysics. In recent calculations the nuclear level density -- as an important ingredient to the statistical model (Hauser-Feshbach) -- has…

Astrophysics · Physics 2016-08-30 T. Rauscher , F. -K. Thielemann , K. -L. Kratz

A new model for calculating nuclear level densities is investigated. The single-nucleon spectra are calculated in a relativistic mean-field model with energy-dependent effective mass, which yields a realistic density of single-particle…

Nuclear Theory · Physics 2008-11-26 R. Pezer , A. Ventura , D. Vretenar

Spin and parity dependent nuclear level densities (NLDs) are obtained for configuration interaction shell model using a numerically efficient spectral distribution method. The calculations are performed for $^{24}$Na, $^{25,26,27}$Mg nuclei…

Nuclear Theory · Physics 2024-02-15 T. Ghosh , Sangeeta , B. Maheshwari , G. Saxena , B. K. Agrawal

The main formalisms of partial level densities (PLD) used in preequilibrium nuclear reaction models, based on the equidistant spacing model (ESM), are considered. A collection of FORTRAN77 functions for PLD calculation by using 14…

Computational Physics · Physics 2009-10-31 M. Avrigeanu , V. Avrigeanu

A method for making realistic estimates of the density of levels in even-even nuclei is presented making use of the Monte Carlo shell model (MCSM). The procedure follows three basic steps: (1) computation of the thermal energy with the…

Nuclear Theory · Physics 2009-10-30 W. E. Ormand

An electron density functional approach for the calculation of the nuclear multipole moments is presented. The electronic matrix elements entering the experimentally observed hyperfine electron-nucleus interaction constants in atoms are…

Nuclear Theory · Physics 2007-05-23 R. L. Pavlov , P. P. Raychev , V. P. Garistov , M. Dimitrova-Ivanovich , J. Maruani

A simple and efficient method to treat nuclear pairing correlations within a simple Hartree-Fock--plus-BCS description is proposed and discussed. It relies on the fact that the intensity of pairing correlations depends crucially on level…

Nuclear Theory · Physics 2024-09-18 Meng-Hock Koh , Philippe Quentin

In the independent-particle model, the nuclear level density is determined from the neutron and proton single-particle level densities. The single-particle level density for the positive-energy continuum levels is important at high…

Nuclear Theory · Physics 2009-11-10 R. J. Charity , L. G. Sobotka

We present some results and remarks based on a combinatorial approach of the evaluation of the nuclear level density. First, we show that it is possible to extract some reliable information from the output of the program whose rough data…

Nuclear Theory · Physics 2007-05-23 Bernard PICHON CNRS

Starting from an independent-particle model with a finite and arbitrary set of single-particle energies, we develop an analytical approximation to the many-body level density $\rho_A(E)$ and to particle-hole densities. We use exact…

Nuclear Theory · Physics 2013-09-30 Adriana Pálffy , Hans A. Weidenmüller

The seniority scheme has been shown to be extremely useful for the classification of nuclear states in semi-magic nuclei. The neutron-proton ($np$) correlation breaks the seniority symmetry in a major way. As a result, the corresponding…

Nuclear Theory · Physics 2012-10-03 C. Qi , J. Blomqvist , T. Bäck , B. Cederwall , A. Johnson , R. J. Liotta , R. Wyss

Level density $\rho(E,N,Z)$ is calculated for the two-component close- and open-shell nuclei with a given energy $E$, and neutron $N$ and proton $Z$ numbers, taking into account pairing effects within the microscopic-macroscopic approach…

Nuclear Theory · Physics 2023-08-16 A. G. Magner , A. I. Sanzhur , S. N. Fedotkin , A. I. Levon , U. V. Grygoriev , S. Shlomo

The level density is among the most important statistical nuclear properties. It appears in Fermi's golden rule for transition rates and is an important input to the Hauser-Feshbach theory of compound nucleus reactions. We discuss empirical…

Nuclear Theory · Physics 2022-01-05 Y. Alhassid

High precision atomic data is indispensable for experiments involving studies of fundamental interactions, astrophysics, atomic clocks, plasma science, and others. We develop new parallel atomic structure codes and explore the difficulties…

Atomic Physics · Physics 2021-03-11 C. Cheung , M. S. Safronova , S. G. Porsev

A systematic study of nuclear level densities has been carried out within the relativistic Hartree-Bogoliubov plus combinatorial framework. Calculations were performed for even-even nuclei with available experimental data, based on the…

Nuclear Theory · Physics 2026-05-07 Pengxiang Du , Jian Li

The shell model Monte Carlo (SMMC) method enables calculations in model spaces that are many orders of magnitude larger than those that can be treated by conventional methods, and is particularly suitable for the calculation of level…

Nuclear Theory · Physics 2015-06-18 Y. Alhassid , M. Bonett-Matiz , S. Liu , A. Mukherjee , H. Nakada

The energy spectra of neutrons, protons, and alpha-particles have been measured from the d+59Co and 3He+58Fe reactions leading to the same compound nucleus, 61$Ni. The experimental cross sections have been compared to Hauser-Feshbach model…

Nuclear Experiment · Physics 2008-11-26 A. V. Voinov , S. M. Grimes , C. R. Brune , M. J. Hornish , T. N. Massey , A. Salas

We investigate unnatural-parity high-spin states in neutron-rich Cr and Fe isotopes using large-scale shell-model calculations. These shell-model calculations are carried out within the model space of $fp$-shell + $0g_{9/2}$ + $1d_{5/2}$…

Nuclear Theory · Physics 2015-06-23 Tomoaki Togashi , Noritaka Shimizu , Yutaka Utsuno , Takaharu Otsuka , Michio Honma