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Los Alamos National Laboratory is operated by the University o for the United States Department of Energy under contract W-7 t g 0 f o m i a-ENG-36. An Afirmative Action/Eqital Opporttmity Employer This report was prepared QS an account of work sponsored by an agency of the United States Government. Neither The Regents of the University of California, the United States Gowrnment nor anyagencythmof,noranyoftheiremployees, makesanywarrrmty, expressorimplied,orassumesany

Shock‐wave data have been obtained for the following rocks: one albitite, one anorthosite, two bronzitites, two diabases, two dunites, two eclogites, one granite, and one Jadeite. The experimental pressure range is from slightly over 0.1 to about 1.0 Mb. There is evidence that all rocks investigated exhibit a phase change. It is estimated that the transformations occur at about 0.1 Mb for the low‐density rocks and between 0.3 and 0.6 Mb for the high‐density rocks. A single‐shock Hugoniot consistent with the data has been determined for the high‐pressure modification of some of these rocks. These equations of state are compared with similar equations of state derived from geophysical data for the earth. This comparison supports the model of a mantle composed of high‐pressure modifications of these basic rocks with an iron content lying somewhere between that of Twin Sisters dunite and Hortonolite dunite. Other thermodynamic quantities have been calculated based on estimates of the specific heat and the Grüneisen parameter.

Plane-wave explosive systems were used to accelerate thin metal plates to high velocities. Shock pressures resulting from the collision of these driver plates with a stationary target plate are approximately three times greater than the original shock pressure in the driver plate. The photographic flash-gap technique was used to record velocities associated with the shock waves. The new experimental data extend the Hugoniot loci into the one-to two-megabar region for 19 metallic elements: Ag, Au, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sn, Th, Ti, Tl, V, W, Zn, Bi, Fe, Sb. The Hugoniot P, V, E data have been extended to a more complete P, V, E, T equation of state by use of the Mie-Grüneisen theory. The thermodynamic variable, γ=V(∂P/∂E)v, necessary for this extension, was obtained by solving the Dugdale-MacDonald relation.

The structures of the aqueous nitrate complexes of Pu(IV) have been studied by extended X-ray absorption fine-structure (EXAFS) at nitric acid concentrations of 3, 8, and 13 M. Systematic changes in the EXAFS spectra demonstrate the trends of increasing nitrate ligation and decreasing water ligation as a function of increasing nitric acid concentration. The coordination numbers of the nitrogens and noncoordinating oxygens are consistent with previous studies in which the principal species were found to be the di-, tetra-, and hexanitrato complexes in these solutions. The Pu(IV) nitrato complexes in nitric acid appear to have similar actinide−nitrate structures as seen in the solid state structures of analogous thorium and neptunium nitrate compounds in which the nitrate ligands are planar and bidentate, and the central actinide atom is in the plane of the nitrates. The nitrates are distorted with respect to free nitrate in that the nitrogen−oxygen bond length of the noncoordinating oxygen is significantly shorter than the nitrogen−oxygen bond lengths of the coordinated oxygens. The plutonium in these complexes is highly coordinated with coordination numbers of 11−12 for the first shell of oxygen nearest neighbors. The average plutonium−oxygen (nitrate) bond length is 2.49 Å, and the average plutonium−oxygen (water) bond length is estimated to be 2.38 Å.