13 research outputs found
Monte Carlo results for the hydrogen Hugoniot
We propose a theoretical Hugoniot obtained by combining results for the
equation of state (EOS) from the Direct Path Integral Monte Carlo technique
(DPIMC) and those from Reaction Ensemble Monte Carlo (REMC) simulations. The
main idea of such proposal is based on the fact that DPMIC provides
first-principle results for a wide range of densities and temperatures
including the region of partially ionized plasmas. On the other hand, for lower
temperatures where the formation of molecules becomes dominant, DPIMC
simulations become cumbersome and inefficient. For this region it is possible
to use accurate REMC simulations where bound states (molecules) are treated on
the Born-Oppenheimer level using a binding potential calculated by Kolos and
Wolniewicz. The remaining interaction is then reduced to the scattering between
neutral particles which is reliably treated classically applying effective
potentials. The resulting Hugoniot is located between the experimental values
of Knudson {\textit{et al.}} \cite{1} and Collins {\textit{et al.}} \cite{2}.Comment: 10 pges, 2 figures, 2 table
Path integral Monte Carlo calculations of helium and hydrogen-helium plasma thermodynamics and of the deuterium shock Hugoniot
In this work we calculate the thermodynamic properties of hydrogen-helium
plasmas with different mass fractions of helium by the direct path integral
Monte Carlo method. To avoid unphysical approximations we use the path integral
representation of the density matrix. We pay special attention to the region of
weak coupling and degeneracy and compare the results of simulation with a model
based on the chemical picture. Further with the help of calculated deuterium
isochors we compute the shock Hugoniot of deuterium. We analyze our results in
comparison with recent experimental and calculated data on the deuterium
Hugoniot.Comment: 7 pages, 5 Postscript figures, accepted for publication in J. Phys.
A: Math. Ge