Freezings and Compressions to 50,000 kg/cm2
About: This article is published in Journal of Chemical Physics.The article was published on 1941-11-01. It has received 51 citations till now.
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TL;DR: In this article, high explosives were used to drive strong shock waves into various liquids, and a moving image camera was employed to determine velocities associated with the shock waves, which were transformed to pressure-compression points by applying the conservation relations.
Abstract: High explosives were used to drive strong shock waves into various liquids, and a moving‐image camera was employed to determine velocities associated with the shock waves. The measured velocities are transformed to pressure‐compression points by applying the conservation relations. The pressures attained vary among the 15 liquids studied but are typically in the range 50 kilobars to 150 kilobars. For water, more extensive experimentation suffices to determine the Hugoniot curve from 30 kilobars to 450 kilobars. The highest pressure for each of the liquids extends the available data range from static experimentation several fold.A shock‐wave‐reflection experimental method is described, the purpose of which is to measure the useful thermodynamic variable (ΔH/ΔV)P at high pressures. Results are given for water.Qualitative experiments to study the transparency of shocked water, carbon tetrachloride, ethyl alcohol, and benzene are reported.
258 citations
TL;DR: The crystal structure was solved by generating all possible molecular packing configurations and calculating structure factors, reliability factors, and packing energies for each configuration, which produced a unique solution for the molecular packing of benzene II.
Abstract: Crystals of a high-pressure form of benzene (benzene 11) were grown in the diamond-anvil pressure cell at elevated temperature and pressure from the transition of solid I to solid II. X-ray precession data were obtained from a single-crystal in the high-pressure cell. At 21°C and about 25 kilobars, benzene II crystallizes in the monoclinic system with a = 5.417 ± 0.005 angstroms (S.D.), b = 5.376 ± 0.019 angstroms, c = 7.532 ± 0.007 angstroms, β = 110.00° ± 0.08°, space group P21/ c, Pc= 1.26 grams per cubic centimeter. The crystal structure was solved by generating all possible molecular packing configurations and calculating structure factors, reliability factors, and packing energies for each configuration. This procedure produced a unique solution for the molecular packing of benzene II.
161 citations
TL;DR: In this article, the authors used the impedance match method to transform pressure and volume data for benzene, carbon disulfide, carbon tetrachloride, and liquid nitrogen.
Abstract: Hugoniot data to several hundred kilobar have been obtained for benzene, carbon disulfide, carbon tetrachloride, and liquid nitrogen. Standard high explosive techniques were used for generating the shock waves. Experimentally measured quantities were transformed to pressure and volume data by the impedance match method. The shock‐particle velocity data for the liquids are described by a linear relationship, however, a quadratic in particle velocity also provides an adequate representation of the data for carbon tetrachloride and liquid nitrogen. Benzene undergoes a transition at 133 kbar and carbon disulfide at 62 kbar. These transitions are accompanied by a volume decrease of approximately 16%. A double shock‐wave structure, observed in many solids which undergo a transition, was not observed in benzene and carbon disulfide. There is some evidence that carbon tetrachloride and liquid nitrogen undergo a transition at 165 and 135 kbar, respectively. Hugoniot curves calculated from a Lennard‐Jones and Devonshire (6‐9) and a modified Buckingham exp‐6 intermolecular potential fit the liquid nitrogen experimental Hugoniot curve between 20 and 170 kbar.
147 citations
TL;DR: In this paper, the partial molal volumes of benzene, methane, ethane and propane in water solution have been determined at temperatures ranging from 10 −40°C. All the volumes measured were less than those of the same hydrocarbons in nonpolar solvents.
Abstract: The partial molal volumes of benzene, methane, ethane and propane in water solution have been determined at temperatures ranging from 10—40°C. All the volumes measured were less than those of the same hydrocarbons in nonpolar solvents. This decrease in volume is explained in terms of the abnormally high internal pressure of water, which decreases the free volume available to the hydrocarbon molecules. The temperature dependence of the partial molal volumes of the aliphatic hydrocarbons differs sharply from that of benzene. It is suggested that this is caused by a difference in solution structure in the two cases.
146 citations
TL;DR: In this article, the authors investigated the properties of benzene at room temperature as a function of pressure up to 25 GPa in diamond anvil cells by Raman scattering and powder x-ray diffraction techniques.
Abstract: Crystalline benzene has been investigated at room temperature as a function of pressure up to 25 GPa in diamond anvil cells by Raman scattering and powder x‐ray diffraction techniques. The concomitant spectroscopic and crystallographic results show the existence of numerous pressure‐induced phases. Changes in the profiles of the Raman spectra and in the x‐ray diffraction patterns, as well as changes in the variations of the Raman frequencies and the cell parameters with pressure indicate two first‐order phase transitions at 1.4±0.1 and 4±1 GPa and a second‐order one at 11±1 GPa. At 24 GPa the x‐ray diffraction pattern seems to indicate the existence of a new phase. Two monoclinic structures are proposed for the phases above 1.5 GPa, in addition to the already known one. From these data, molar volume has been determined as a function of pressure and the Gruneisen parameters have been inferred in the different phases. Their pressure dependences are analyzed in the light of theoretical predictions. Arguments are given for a phase transformation at normal pressure and below 140 K or at room temperature below 1 GPa. A schematic P–T phase diagram is suggested and a controversy on the nature of the triple points located on the melting curve is clarified.
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