Linear-mixing model for shock-compressed liquid deuterium

Journal Article · Wed Jul 01 04:00:00 EDT 1998 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.58.669· OSTI ID:638786

Ross, M ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

A model has been developed for the equation of state of deuterium that builds in the correct limiting behavior for the molecular fluid at low pressure and extends smoothly through dissociation to the very high-density monatomic-metallic fluid. The key assumption is that the Helmholtz free energy of the dissociating mixture is a function that can be approximated by the composition average of the free energy of the pure molecular and metallic hydrogen equations of state. The composition is determined by minimizing the free energy. In comparison to earlier studies this model leads to an enhancement of molecular dissociation and a lowering of shock temperatures and pressures. Calculations for shock-compressed liquid deuterium are in agreement with experiments to a pressure of 2.1 Mbar. At about 1 Mbar and 20thinsp000 K liquid deuterium is 90{percent} dissociated and is a nearly degenerate metal. The model predicts that molecular dissociation will lead to negative values of ({partial_derivative}P/{partial_derivative}T){sub V} in the range 4000 to 10thinsp000 K and volumes below 7 cc/mol. This feature suggests the formation of covalently bonded species in the partially dissociated mixture. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 638786
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 2 Vol. 58; ISSN 0163-1829; ISSN PRBMDO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DEUTERIUM
DISSOCIATION
EQUATIONS OF STATE
FREE ENERGY
LIQUIDS
MIXING
PRESSURE DEPENDENCE
SHOCK WAVES
TEMPERATURE DEPENDENCE