Year: 2024
Type: preprint
Abstract: Accurate modeling in the warm dense matter regime is a persistent challenge with the most detailed models such as quantum molecular dynamics and path integral Monte Carlo being immensely computationally expensive. Density functional theory (DFT)-based average atom models (AAM) offer significant speed-ups in calculation times while still retaining fair accuracy in evaluating equations of state, mean ionizations, and more. Despite their success, AAMs struggle to precisely account for electronic interactions -- in particular, they do not account for effects on the kinetic energy arising from overlaps in neighboring atom densities. We aim to enhance these models by including such interactions via the non-additive kinetic potential $v^{\rm nadd}$ as in DFT embedding theories. $v^{\rm nadd}$ can be computed using Thomas-Fermi, von Weizsäcker, or more sophisticated kinetic energy functionals. The proposed model introduces $v^{\rm nadd}$ as a novel interaction term in existing ion-correlation models, which include interactions beyond the central atom. We have applied this model to hydrogen at 5 eV and densities ranging 0.008 to 0.8 g/cm$^3$, and investigated the effects of $v^{\rm nadd}$ on electron densities, Kohn-Sham energy level shifts, mean ionization, and total energies.
Source: arXiv (Cornell University)
Authors: Yunus, Sameen, Strubbe, David A.
Institution: University of California, Merced
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G3711026398, MRI: Acquisition of Pinnacles -- Raising Research Computing to New Heights in California's Central Valley, CONSORTIUM FOR HIGH ENERGY DENSITY SCIENCE:
THE OVERARCHING OBJECTIVE OF THE CONSORTIUM FOR HIGH ENERGY DENSITY SCIENCE (CFHEDS) IS TO
ESTABLISH A SUSTAINABLE RECRUITING PIPELINE OF NEW SCIENTISTS INTO NNSA NATIONAL LABORATORIES WHO ARE WELL
PREPARED TO CONDUCT MISSION-CRITICAL RESEARCH IN HEDS. CFHEDS IS ALSO IMPROVING THE CAPACITY OF MINORITY-
SERVING INSTITUTIONS (MSIS) TO PREPARE SCIENTISTS FOR RESEARCH CAREERS IN HIGH ENERGY DENSITY (HED) SCIENCE, A
KEY ASPECT OF NUCLEAR SECURITY AND NUCLEAR SCIENCE.
THE LEAD ENTITY IN THE CONSORTIUM IS FLORIDA A&M UNIVERSITY (FAMU), AN MSI WITH EXPERTISE IN HED SCIENCE AND A
HISTORY OF COLLABORATING WITH LAWRENCE LIVERMORE NATIONAL LABORATORY (LLNL). THE CONSORTIUM ALSO INCLUDES THE
UNIVERSITY OF CALIFORNIA, MERCED (UC MERCED), AN MSI LOCATED A SHORT DRIVE FROM LLNL WHICH OFFERS
UNDERGRADUATE AND GRADUATE PROGRAMS IN PHYSICS AND CHEMISTRY AND HAS STRENGTHS IN COMPUTATION AND THEORY,
AND MOREHOUSE COLLEGE, AN UNDERGRADUATE INSTITUTION LOCATED IN ATLANTA, GEORGIA, THAT PRODUCES MORE HOLDERS OF
BS DEGREES IN PHYSICS THAN ANY OTHER MSI INSTITUTION. LLNL IS AN INTERNATIONAL LEADER IN HED SCIENCE AND HOME
TO THE NATIONAL IGNITION FACILITY (NIF) AND THE JUPITER LASER FACILITY (JLF), AS WELL AS THE HED SCIENCE CENTER,
WHICH FOSTERS COLLABORATIONS BETWEEN LLNL’S HED SCIENCE EXPERTS AND THE ACADEMIC COMMUNITY.
OpenAlex ID: W4402955457