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Title: Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.

Abstract

No abstract prepared.

Authors:
 [1];  [2];  [3]; ;
  1. (Universitat Rostock, Institut fur Physik, D-18051 Rostock, Germany)
  2. (Universitat Rostock, Institut fur Physik, D-18051 Rostock, Germany)
  3. (Universitat Rostock, Institut fur Physik, D-18051 Rostock, Germany)
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
908065
Report Number(s):
SAND2007-1207J
TRN: US0703537
DOE Contract Number:
AC04-94AL85000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proposed for publication in Physical Review Letters.
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; HELIUM; QUANTUM MECHANICS; MOLECULAR DYNAMICS METHOD; FLUIDS; PHASE TRANSFORMATIONS

Citation Formats

Redmer, Ronald, Holst, Bastian, Keitzmann, Andre, Desjarlais, Michael Paul, and Mattsson, Thomas Kjell Rene. Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.. United States: N. p., 2007. Web.
Redmer, Ronald, Holst, Bastian, Keitzmann, Andre, Desjarlais, Michael Paul, & Mattsson, Thomas Kjell Rene. Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.. United States.
Redmer, Ronald, Holst, Bastian, Keitzmann, Andre, Desjarlais, Michael Paul, and Mattsson, Thomas Kjell Rene. Thu . "Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.". United States. doi:.
@article{osti_908065,
title = {Quantum molecular dynamics simulations for the nonmetal-to-metal transition in fluid helium.},
author = {Redmer, Ronald and Holst, Bastian and Keitzmann, Andre and Desjarlais, Michael Paul and Mattsson, Thomas Kjell Rene},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Proposed for publication in Physical Review Letters.},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}
  • We have performed quantum molecular dynamics simulations for dense helium to study the nonmetal-to-metal transition at high pressures. We present new results for the equation of state and the Hugoniot curve in the warm dense matter region. The optical conductivity is calculated via the Kubo-Greenwood formula from which the dc conductivity is derived. The nonmetal-to-metal transition is identified at about 1 g/cm{sup 3}. We compare with experimental results as well as with other theoretical approaches, especially with predictions of chemical models.
  • We have performed direct measurements and quantum molecular-dynamics simulations for expanded aluminum at densities two to nine times lower than the normal solid density and internal energies ranging from 7 to 70 kJ/g. The simulation results were found to be in good agreement with the experimental data and reproduce well the main trends observed in the measured dependencies of the electrical resistivity and pressure versus internal energy along isochores. A systematic study of the optical conductivity spectra, one-particle density of states, and the distributions of the electronic charge over supercell shows that the transition of expanded aluminum to a nonmetallicmore » state takes place close to the density at which the constant volume derivative of the electrical resistivity on internal energy becomes negative.« less
  • Abstract not provided.
  • We have carried out small angle x-ray scattering experiments of expanded fluid Hg in the metal-nonmetal (M-NM) transition region around 9.0 g cm{sup -3}. Increase of small angle scattering intensity following the Ornstein-Zernike equation is clearly observed in the M-NM transition region as well as near the liquid-vapor critical point at 5.8 g cm{sup -3}. The short-range correlation length, R, becomes twice as large in the M-NM transition region as in the critical region. The enhancement of R in expanded fluid Hg suggests a new type of fluctuations reflecting a first-order M-NM transition.
  • The nature of the superconducting transition temperature (and conductivity) oscillations that arise in a metal-nonmetal film system as the thickness of the nonmetallic film is increased is considered. It is shown that the phenomenon is connected with the oscillations of the electron density of states in the metal caused by the oscillations of the boundary condition for the wave function at the metal-nonmetal film interface. The latter is connected with the nature of the motion and reflection of an electron in a semiconducting, or a semimetallic, film. The question of the period and amplitude of the T/sub c/ oscillations ismore » analyzed in detail. The results obtained allow the explanation of all the distinctive features of the phenomenon, which was discovered by Mikheeva, Golyanov, et al. and Sixl.« less