« lessĪ new parameterization for density functional tight binding (DFTB) theory, lanl31, has been developed for molecules containing carbon, hydrogen, nitrogen, and oxygen. Temperature calculations are included although there is some uncertainty as to their accuracy because of a lack of experimental temperature data. Methods employed to match the calculations to the data in order to establish the values of various adjustable parameters are detailed. Both equations are based on the use of a Murnaghan isotherm relation along with assumed forms for specific heat and the Gruneisen parameter. This paper describes the development of these equations of state along with comparisons of calculated Hugoniot information to measured data available in more » the literature. ![]() In order to learn more about the anomalous behavior as it relates to a shock-induced chemical reaction, it was necessary to develop equations of state for both the unreacted liquid and the reaction products. This behavior has been explained by either a phase transition to a ''black solid CS/sub 2/ '' or a decomposition chemical reaction. Liquid carbon disulfide (CS/sub 2/) is known to exhibit unusual behavior when it is shock compressed to pressures of approximately 6.0 GPa. Based on an analysis of the states achieved in the two-wave structure, the reaction is inferred to be much more temperature than pressure dependent, adding strength to the hypothesis that a chemical reaction rather than a phase transition is occurring. The Hugoniot cusp at the onset of the high compressibility region is estimated to occur at about 4.6 GPa, a value somewhat lower than previously reported. Upon reflection of the initial shock from the sapphire anvil, an evolving two-wave structure was observed, a direct result of the increased compressibility. The ''unreacted'' Hugoniot was deduced from measurements made as the initial shock traversed the CS/sub 2/. Electromagnetic velocity gauges were used more » to monitor the particle velocity history at several Lagrangian positions in the liquid. Shock experiments based on this idea used a sapphire-faced projectile to impact a plastic cell containing the CS/sub 2/, constructed with a sapphire back plate which served as an anvil to produce the second shock. ![]() An idealized double-shock experiment is proposed to probe the process using conventional shock measurables. One candidate explanation for this is that the CS/sub 2/ reacts chemically with an accompanying negative volume change. Receipt Date: 31-DEC-68 Country of Publication: United States Language: English Subject: 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY BENZENE CARBON SULFIDES CARBON TETRACHLORIDE COMPRESSION DENSITY HIGH TEMPERATURE HUGONIOT CURVE LIQUIDS NITROGEN PRESSURE SHOCK WAVES TEMPERATURE NITROGEN/compression of liquid, by shock waves at 75K, Hugoniot data on CARBON SULFIDES/compression by shock waves at 300K, Hugoniot data on SHOCK WAVES/effects on compression of benzene, carbon disulfide, carbon tetrachloride, and liquid nitrogen, Hugoniot data on CARBON TETRACHLORIDE/compression by shock waves at 300K, Hugoniot data on BENZENE/compression by shock waves at 300K, Hugoniot data onĬarbon disulfide (CS/sub 2/) is known to encounter a region of high compressibility upon shock loading which is conjectured to accompany a reaction precipitated by the shock loading. (LANL), Los Alamos, NM (United States) Sponsoring Org.: US Atomic Energy Commission (AEC) OSTI Identifier: 4536170 Report Number(s): LA-3915 NSA Number: NSA-22-027624 DOE Contract Number: W-7405-ENG-36 Resource Type: Thesis/Dissertation Resource Relation: Other Information: Thesis. Publication Date: Research Org.: Los Alamos National Lab.
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