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Title: Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons

Abstract

Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.

Authors:
 [1];  [2];  [3];  [4];  [5];  [4];  [1];  [2];  [6];  [7]
  1. Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States)
  2. (United States)
  3. (Bulgaria)
  4. Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States)
  5. (Turkey)
  6. (Poland)
  7. Institute of Theoretical Physics, Warsaw University, Warsaw (Poland)
Publication Date:
OSTI Identifier:
20951187
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 13; Other Information: DOI: 10.1103/PhysRevLett.98.132502; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; BINDING ENERGY; COMPARATIVE EVALUATIONS; DEGREES OF FREEDOM; DENSITY FUNCTIONAL METHOD; EVEN-EVEN NUCLEI; NUCLEAR MATTER; PROTON-NEUTRON INTERACTIONS

Citation Formats

Stoitsov, M., Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Cakirli, R. B., Department of Physics, University of Istanbul, Istanbul, Casten, R. F., Nazarewicz, W., Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, Institute of Theoretical Physics, Warsaw University, Warsaw, and Satula, W. Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.132502.
Stoitsov, M., Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Cakirli, R. B., Department of Physics, University of Istanbul, Istanbul, Casten, R. F., Nazarewicz, W., Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, Institute of Theoretical Physics, Warsaw University, Warsaw, & Satula, W. Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons. United States. doi:10.1103/PHYSREVLETT.98.132502.
Stoitsov, M., Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Cakirli, R. B., Department of Physics, University of Istanbul, Istanbul, Casten, R. F., Nazarewicz, W., Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, Institute of Theoretical Physics, Warsaw University, Warsaw, and Satula, W. Fri . "Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons". United States. doi:10.1103/PHYSREVLETT.98.132502.
@article{osti_20951187,
title = {Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional, and Local Comparisons},
author = {Stoitsov, M. and Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 and Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia and Cakirli, R. B. and Department of Physics, University of Istanbul, Istanbul and Casten, R. F. and Nazarewicz, W. and Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 and Institute of Theoretical Physics, Warsaw University, Warsaw and Satula, W.},
abstractNote = {Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.},
doi = {10.1103/PHYSREVLETT.98.132502},
journal = {Physical Review Letters},
number = 13,
volume = 98,
place = {United States},
year = {Fri Mar 30 00:00:00 EDT 2007},
month = {Fri Mar 30 00:00:00 EDT 2007}
}
  • Calculations of nuclear masses, using nuclear density functional theory, are presented for even-even nuclei spanning the nuclear chart. The resulting binding energy differences can be interpreted in terms of valence proton-neutron interactions. These are compared globally, regionally, and locally with empirical values. Overall, excellent agreement is obtained. Discrepancies highlight neglected degrees of freedom and can point to improved density functionals.
  • Lanthanum tungstate (La 28–xW 4+xO 54+δ) is a good proton conductor and exhibits a complex fluorite-type structure. To gain further understanding of the short-range order in the structure we correlate the optimized configurations obtained by density functional theory (DFT) with the experimental atomic pair distribution function analysis (PDF) of time-of-flight neutron and synchrotron X-ray data, collected at room temperature. The local atomic arrangements cannot be described by means of any average symmetric structure. Tungsten forms WO 6 octahedra in alternating directions, La1 is mainly 8-fold coordinated in relatively symmetric cubes, and La2 is coordinated with 6 or 7 oxygens inmore » heavily distorted cubes. Both DFT and PDF confirm that the excess tungsten (x) is incorporated in La2 (1/4, 1/4, 1/4) sites in the La 27W 5O 55.5 composition. This additional tungsten can be considered as a donor self-dopant in the material and has implications to the conducting properties and the defect structure.« less
  • Density functional theory (DFT) in the commonly used local density or generalized gradient approximation fails to describe van der Waals (vdW) interactions that are vital to organic, biological, and other molecular systems. Here, we propose a simple, efficient, yet accurate local atomic potential (LAP) approach, named DFT+LAP, for including vdW interactions in the framework of DFT. The LAPs for H, C, N, and O are generated by fitting the DFT+LAP potential energy curves of small molecule dimers to those obtained from coupled cluster calculations with single, double, and perturbatively treated triple excitations, CCSD(T). Excellent transferability of the LAPs is demonstratedmore » by remarkable agreement with the JSCH-2005 benchmark database [P. Jurecka et al. Phys. Chem. Chem. Phys. 8, 1985 (2006)], which provides the interaction energies of CCSD(T) quality for 165 vdW and hydrogen-bonded complexes. For over 100 vdW dominant complexes in this database, our DFT+LAP calculations give a mean absolute deviation from the benchmark results less than 0.5 kcal/mol. The DFT+LAP approach involves no extra computational cost other than standard DFT calculations and no modification of existing DFT codes, which enables straightforward quantum simulations, such as ab initio molecular dynamics, on biomolecular systems, as well as on other organic systems.« less
  • By using an exponential function to simulate the residual proton-neutron interaction between valence nucleons, we derive a new set of local mass formulas that are competitive with the Garvey-Kelson mass relations for relating neighboring nuclear masses.