CARNEGIE/DOE ALLIANCE CENTER

A Center of Excellence for High Pressure Science and Technology Supported by the Stockpile Stewardship Academic Alliances Program of DOE/NNSA

Year Three Annual Report

September 2006

Russell J. Hemley, Director Ho-kwang Mao, Associate Director Stephen A. Gramsch, Coordinator

Carnegie/DOE Alliance Center (CDAC): A CENTER OF EXCELLENCE FOR HIGH PRESSURE SCIENCE AND TECHNOLOGY

YEAR THREE ANNUAL REPORT

1. Overview 1.1 Mission of CDAC 3 1.2 Highlights from Year 3 4 1.3 Year 3 Work Plan and Milestones 6 2. Scientific Progress 2.1 High P-T Phase Relations and Structures 10 2.2 P-V-T EOS Measurements 19 2.3 Phonons, Vibrational Thermodynamics and Elasticity 22 2.4 Plasticity, Yield Strength and Deformation 26 2.5 Electronic and Magnetic Structure and Dynamics 27 2.6 High P-T Chemistry 36 3. Education, Training, and Outreach 3.1 CDAC Graduate Students and Post-doctoral Associates 40 3.2 CDAC Collaborators 43 3.3 Undergraduate Student Participation 47 3.4 DC Area High School Outreach 49 3.5 Synergy of 21st Century High-Pressure Science and Technology Workshop 50 3.6 Visitors to CDAC 56 3.7 High Pressure Seminars 58 4. Technology Development 4.1 High P-T Experimental Techniques 60 4.2 Facilities at Brookhaven, LANSCE, and Carnegie 64 4.3 Commissioning and Activities at HPCAT 66 5. Interactions with NNSA/DP National Laboratories 5.1 Overview 67 5.2 Academic Alliance and Laboratory Collaborations 69 6. Management and Oversight 6.1 CDAC Organization and Staff 71 6.2 CDAC Oversight 73 6.3 Second Year Review 74 7. Plans for Year 4 and Beyond 7.1 Scientific and Educational Focus 75 7.2 Implementation of CDAC Phase II 75 7.3 HPCAT Upgrade 76

Appendix I CDAC Publications and Presentations for Year 3 81 Appendix II CDAC Synchrotron Users/Experiments (APS and NSLS) for Year 3 99 References 112

2 1. OVERVIEW 1.1 Mission of CDAC High P-T materials research is critical to the mission of the National Nuclear Security Administration in science-based stockpile stewardship1. The program encompasses a broad range of problems and materials – d- and f-electron elements and alloys, low-Z molecular compounds, energetic materials and detonation products, dense hydrogen, metal oxides and hydrides, and bulk materials as well as composites and interfaces. Information on these materials in crystalline, liquid, and amorphous phases and examination of phase transitions, equations of state, phonon dynamics, elasticity and plasticity, electronic and magnetic structures, and chemical reactions are essential. Moreover, addressing these problems requires the training of the next generation of scientists. The proper training of these students requires in turn their access to state-of-the-art facilities that may not be available to research groups in the NNSA Labs or in conventional academia. The Carnegie/DOE Alliance Center – CDAC – was created to support this NNSA mission. Now completing its third year, CDAC continues to address these important needs of the NNSA in scientific research and training. The success of the past year has allowed us to grow and bring a broader range of universities into the alliance. CDAC is managed by Russell J. Hemley (Director), Ho-kwang Mao (Associate Director), and Stephen Gramsch (Coordinator). CDAC consists of six formal partners together with Carnegie (the CDAC Academic Partners): Princeton University (Tom Duffy), University of Chicago (Dion Heinz), University of Illinois (Dana Dlott), University of Alabama - Birmingham (Yogesh Vohra), University of California - Berkeley (Hans-Rudolf Wenk), and California Institute of Technology (Brent Fultz). Starting with Year 4, four new academic partners have joined CDAC: New Mexico State University (Kanani Lee), Florida International University (Surendra Saxena), Texas Tech University (Yanzhang Ma), University of Nevada - Reno (Dhanesh Chandra), and Arizona State University (Jeffrey Yarger). Scientists at the National Labs (the CDAC Laboratory Partners) obtain beam time and technical training, and access to ongoing high P-T technique development at HPCAT, the dedicated high-pressure synchrotron x-ray facility at the Advanced Photon Source (APS). Laboratory scientists also take advantage of facilities at Carnegie (including NSLS). There is active cooperation with the Lujan Center in the development of high P-T neutron scattering. Finally, CDAC has an extensive list of collaborators from some 145 institutions around the world.

Figure 1. Aerial photograph of the Carnegie Institution campus in Washington, D.C. where the Geophysical Laboratory is located.

3 CDAC is developing the next generation of high-pressure techniques and conducting systematic measurements of a full range of physical and chemical phenomena under extreme conditions. HPCAT, the dedicated high-pressure synchrotron x-ray facility at the Advanced Photon Source (APS) at Argonne National Laboratory is led by Ho-kwang Mao (Director) and Guoyin Shen (Project Manager). HPCAT has been developed for high pressure physics, chemistry and materials science, and is a centerpiece of the CDAC scientific program, providing technical developments and critical spectroscopic and diffraction tools. Construction of the two insertion device beamlines has been completed, and the microdiffraction station has been open to general users for nearly three years. Commissioning activities in the areas of x-ray absorption and emission, and resonant and non-resonant inelastic x-ray scattering have taken place, with this station accepting proposals from general users for approximately two years. At this point, well over 281 different users (i.e., from National Labs and academia) have conducted experiments at the facility in these two completed experimental hutches to date. Commissioning activities have been nearly completed on the two bending magnet beamlines, and these two stations will be accepting general users in the first run of 2007. The goal of four independently operating experimental hutches, a cornerstone of the initial HPCAT concept, has now been realized. High-pressure neutron facilities at LANSCE, LANL, synchrotron infrared spectroscopy at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory (BNL), and specialized high-pressure facilities at Carnegie complement this effort. At Carnegie, there are important new developments in high P-T spectroscopy of molecular systems, high P-T cell designs, and CVD diamond growth. Experiments in high-pressure geoscience and planetary science provide valuable insight into problems in stewardship science and provide an important training ground for students and other researchers for future work in the NNSA Laboratory complex. There are also close interactions with theorists at Center institutions, the National Laboratories, and throughout academia. CDAC formally began operations on May 1, 2003 with the first funding year ending January 31, 2004. This report covers activities from the CDAC Academic Partners, Laboratory Partners, and University Collaborators since July 2005. Research carried out by National Lab partners, but done outside of the CDAC facilities, is not included. 1.2 Highlights from Year 3 Outreach and Training CDAC continues to make excellent progress in outreach and training, an important part of its mission. The following are highlights, in particular as it relates to students: • Facilitated continual growth of users at HPCAT. To date, more than 281 users have conducted experimental work at the sector. • Increased the number of CDAC collaborations/facility users. Some 411 outside collaborators from over 145 institutions have worked with us on Stewardship Science-related projects. • Science supported Ph.D. thesis work of 19 students at CDAC partner universities and Carnegie and encouraged career development. • CDAC student, Wendy Mao began an Oppenheimer fellowship at LANL and Jung-fu Lin began a Lawrence Fellowship at LLNL. • CDAC supported the Synergy of 21st Century High-Pressure Science and Technology Workshop at Argonne in May 2006, which featured 59 lectures from leading high pressure scientists from academia and the National Laboratories. • Hosted numerous visitors to other CDAC facilities (e.g., Carnegie and NSLS) for training and technique development and established enhanced and expanded collaborations with high pressure programs at all NNSA Labs. • Hosted undergraduate and high school interns at Carnegie and HPCAT. This past year, eight students were working on CDAC-related research projects.

4 Figure 2. Participants listen to a lecture at the 2006 Synergy of 21st Century High- Pressure Science and Technology Workshop held at the Advanced Photon Source.

Scientific Breakthroughs Some 362 papers have been published since the start of the Center as a result of the support from the grant. This list includes papers describing work carried out by the CDAC Academic Partners, Carnegie research supported by the grant, and research carried out at HPCAT and CDAC facilities at NSLS. (The list does not include the large amount of research performed by high- pressure groups within the National Labs not done at CDAC-supported facilities). These papers included articles published in the major high-impact journals.

• High pressure inelastic scattering of H2O reveals bonding changes and dissociation: LLNL scientists carried out direct measurements of the electronic structure of water. Complementary measurements carried out by LANL and Carnegie reveal x-ray induced dissociation2. • New findings in heavy rare earth metals at high pressure: The Alabama-Birmingham group uncovered new trends in pressure-induced structural phase transformations in the heavy rare earth holmium3. • Tribological properties of metal sulfides: X-ray studies of metal sulfides carried out at Texas Tech reveal new insight into their high-pressure tribological properties4.

• Pressure induced phase transitions in PbTiO3: A team from Carnegie carried out theoretical calculations that predict colossal ferroelectriciy in PbTiO3 under pressure5, which is now being examined by in situ Raman and x-ray techniques 6. • Polymers and their composites: Equations of state of a series of important polymers and composites were measured for the first time using light scattering techniques at LANL and Carnegie7-9. • Effect of shear stress and strain on high P-T transformations of iron: The shear stress and strain on the phase transition in iron was identified by the researchers at Texas Tech10. • Reflectivity of iron at high pressure: Important advances in temperature calibration at high pressure with synchrotron IR reflectivity measurements on iron at high pressure collected by the Heinz group at the University of Chicago at the U2A beamline at NSLS11.

5 • Texture development at high pressure: The Berkeley, Princeton, and Carnegie groups carried out systematic investigation of the texture development in MgSiO3 perovskite12, 13. • Plastic behavior of post-perovskite: Members of the Berkeley, Princeton, and Carnegie teams also reported new insights into the plastic behavior of post-perovskite deep in the Earth’s interior have been reported by CDAC collaborators from Berkeley, Princeton, and Carnegie14. • Magnetic state of hcp iron-nickel: Scientists from Caltech and Carnegie, together with the team at HPCAT, found that the high-pressure hcp phase of Fe-Ni remains non-magnetic, using synchrotron Mössbauer spectroscopy at low temperatures15. • Novel transition metal nitrides: A former CDAC summer undergraduate intern and a team from Carnegie, Universitie Pierre et Marie Curie, and Democritos National Simulation Center synthesized two new transition metal nitrides using laser heated diamond cell techniques16. • Nitrides of platinum and iridium: LLNL scientists used HPCAT to characterize new nitrides, showing that platinum and iridium nitrides contained pairs of single-bonded nitrogen atoms17. • Combining synchrotron IR spectroscopy and dynamic compression: Infrared radiation detectors were tested at U2A beamline to establish the feasibility of real-time infrared measurements during dynamic compression18. • Metal-insular transitions: Carnegie scientists and collaborators studied the antiferromagnetic Bi-based high-Tc parent compound by Raman spectroscopy, x-ray diffraction, and resistivity techniques19. • Morphology tuned ZnS nanobelts: New insights into the behavior of wurtzite-type ZnS have been reported from LANL. The observed mechanisms could enable an understanding of the microscopic mechanisms at work in these materials, with the goal of synthesizing functional nanocomposites with excellent mechanical properties20. • Interface dynamics at high pressure: The Illinois group continues to develop an ultrafast nonlinear vibrational spectroscopic technique to understand the dynamics of interfaces under laser-generated shock waves, and in high static pressures produced in an anvil apparatus21. • X-ray induced synthesis of 8H diamond: LANL scientists collaborating with colleagues from Carnegie and the University of Arizona found that exposure of single crystal graphite to intense synchrotron x-ray radiation results in new polymorphism of carbon22. • Large single crystal CVD diamond: The Carnegie group has continued their work on CVD diamond synthesis for a broad range of applications including both static and dynamic compression in collaboration with teams at SNL and LANL23. • High-pressure gigahertz-ultrasonic interferometry: Advances in gigahertz interferometry at Carnegie provide an important complement to existing techniques for elasticity studies under pressure24 1.3 Work Plan and Milestones for Year 3 CDAC’s mission includes a comprehensive scientific program, education, training and outreach component, and technology development. Within the context of these sections, milestones have been set for each year of CDAC. Nearly all of the Year 3 goals were met, and we are on track for meeting – and in many cases have already met our expectations for Year 4. The Year 3 milestones from the original proposal are listed below in bold. Scientific Program 1. We will fully exploit the laser-heating techniques for determination of the phase relations of high and low-Z materials over the broadest possible P-T range (>300 GPa and

6 >6000 K). The electron, phonon, structural, and molecular bonding transitions of hydrogen from the low-temperature molecular insulating solid to the high-temperature metallic fluid will be elucidated.

High P-T measurements on H2 were extended using laser heating techniques25, 26. The pressure dependence of the H2 band gap and low energy excitons in H2 were directly determined using inelastic x-ray scattering27. Studies by Carnegie and LLNL also led to improved determination of the phase diagram of H2O, and constraints on superionic behavior26, 28. Bonding breakdown of H2O under pressure2 was also identified with these techniques. 2. The liquid-vapor and liquid-liquid critical points and coexistence curves for carbon and metals will be explored at high-pressure and very high temperature (up to 10,000 K). This will by necessity also include direct determination of subsolidus phase transformations and melting relations. The temperature range of laser heating techniques was extended to above 9000 K in studies of carbon29. The equations of state of numerous materials were determined by x-ray diffraction. The equation of state (EOS) of BeH2 was determined by Brillouin scattering30. Complementary experiments were carried out by LLNL colleagues on Be31. 3. In addition, combining laser heating techniques with radial x-ray diffraction will allow detailed measurements of the combined P-T dependence of yield strength and therefore direct information on rheological properties in a hitherto inaccessible domain. Changes at high pressure with time (creep) and temperature (recrystallization) were documented32, 33. In-situ measurements of phase transformations in steels34 and Ti35 at high temperature were performed. 4. Investigations of solubility and phase relations of compounds and mixtures will continue, including incompatible metals that become alloys, and stable compounds that dissociate at ultrahigh pressure and temperature. The discovery of new nitrides provided an excellent example of new compound and alloy formation under pressure.16,17. As discussed above, x-ray-induced and pressure-induced dissociation of H2O was documented2. 5. Real time SFG measurements will be obtained to reveal the chemistry of polymer binder energetic material interfaces. SFG data on the surfaces of the energetic materials HMX and TATB have been obtained36. In addition, new Brillouin and Raman scattering studies of various polymers and energetic materials were completed37,38. 6. The determination of P-T-V EOS of standard materials (begun in Year 2) will be completed and incorporated into the EOS database at LLNL and LANL for hydrocode applications. Expansion of full investigations to other key materials will be integrated with dynamic compression studies and theoretical models (e.g., ASCI). The equations of state for a series of polymeric materials were determined37. As part of this effort, the computational group at Carnegie has computed the thermoelastic properties of Fe as functions of pressure and temperature. We are working with the laboratories to incorporate EOS data obtained in CDAC in laboratory simulations as part of NNSA milestones. 7. Ultrahigh-accuracy and -efficiency diffraction studies will be extended to the lanthanide series and integrated with electronic, magnetic and phonon studies to establish systematics in f-electron systems. Advances in diffraction techniques had led to improved systematics for understanding the high- pressure behavior of these metals. Both LLNL and LANL are using HPCAT to obtain data crucial for improving our understanding of nuclear weapons performance.

7

Figure 3. Personnel from academic institutions that comprise CDAC.

Education and Training 1. Support for education and training of the proposed 14 graduate students will continue, as will the support for the two CDAC post-doctoral fellows. In Year 3, 13 graduate students and two postdoctoral associates were directly supported by funding allocated to the six academic partners. One graduate student supported by LANL and two graduate students supported by LLNL carried out thesis research on CDAC-related topics. In addition, the four new CDAC academic partners have recruited six graduate students and one postdoctoral associate into their groups. As described in Section 3.1, this part of the CDAC education and outreach effort has been extremely productive. At Carnegie, developments in neutron diffraction to be implemented at LANSCE and eventually the Spallation Neutron Source (SNS) are the focus of one postdoctoral fellow working closely with a research scientist. These appointments are more thoroughly discussed in Section 3.1. 2. The summer school/workshop program will be continued. In Year 3, the Synergy of 21st Century High Pressure Science and Technology meeting held at the APS was sponsored in part by CDAC (travel support for student attendees) and also served as a venue for the gathering of CDAC students, postdoctoral associates, academic partners and laboratory

8 partners. The emphasis of this meeting on cutting-edge science complemented the themes outlined in the CDAC Summer School held during Year 2, which focused on core theory and techniques in high pressure science. CDAC will continue to support student attendance at similar meetings. A second CDAC Summer School is anticipated for the summer of 2007, to be coupled with an advisory committee meeting at which time the future of the CDAC educational program will be discussed. 3. A workshop/retreat to plan for the educational program for CDAC beyond year three will be held, following reviews by the Advisory Committee. With the inception of Phase II of the CDAC program in January 2006 following recommendation by the CDAC Advisory Committee, the support of graduate students in the Center has been continued with an increased number of students. Input from the advisory committee therefore will be sought in 2007 (during Year 5) as to the best way for the CDAC educational and outreach program to move forward. Technique Development 1. The sample sizes in DACs above 100 GPa will be improved from the current limit of 10-4 mm3 to 1 mm3, thus enabling neutron diffraction in the megabar range. The Carnegie synthesis of large single crystal CVD diamond has produced diamond single crystals greater than 10 carats23; this development is allowing samples of the sizes mentioned above to be compressed toward the megabar range. Although we have not yet broken the megabar neutron diffraction barrier, we have pressurized very large single crystals for neutron diffraction39. A high pressure test bed for the SNS has been set up at LANSCE. 2. Electron and phonon band structures and transport measurements will be developed at simultaneous high P-T. We continued to make progress on extending single crystal diffraction to higher pressure. Neutron diffraction measurements have been conducted above 30 GPa39 and the combination of large anvil and Kirkpatrick-Baez focusing should make 50 GPa studies possible in Year 4. 3. We will also explore pulsed laser heating experiments and time resolved measurements of IR reflectivity and electrical conductivity, as well as x-ray diffraction. There was important progress in each of these areas. As mentioned above, in situ high P-T x-ray diffraction with laser-heating has been extended to above to above 9000 K40. Pulsed heating/Raman spectroscopy was developed41. SNL and Carnegie have tested time-resolved synchrotron IR spectroscopy. The Carnegie group has developed new electrical methods using FIB technology. 4. New classes of DACs will be developed for comprehensive studies with multiple x-ray, neutron, optical, electrical, and magnetic probes over an extensive P-T range. Several new DACs were developed for integration of multiple probes and for reaching higher P-T conditions. P-V-T calibrations using both optical and x-ray methods were extended at Carnegie73 and through a LLNL/Carnegie collaborations42. 5. Developments launched in Year 2 will be completed including the new opportunities in combined static and dynamic compression. Considerable progress was made in the use of high P-T x-ray diffraction techniques with resistive heating for amorphous phases43. Techniques for obtaining quantitative texture information from single diffraction images, without imposing sample symmetry were extended44. Building on the success of the laser-shock molecular interface studies mentioned above36, high-pressure, grazing incidence cells for use with SFG measurements are being constructed and tested.

9 2. SCIENTIFIC PROGRESS Year 3 of the CDAC program has led to many results in all areas of emphasis. The following sections discuss selected experimental studies supported fully or in part by CDAC and made possible by the Center. Following earlier Annual Reports, the topics are divided into the following six categories: 1. High P-T Phase Relations and Structures 2. P-V-T EOS Measurements 3. Phonons, Vibrational Thermodynamics and Elasticity 4. Plasticity, Yield Strength and Deformation 5. Electronic and Magnetic Structure and Dynamics 6. High P-T Chemistry 2.1 High P-T Phase Relations and Structures Studies at high P-T conditions made possible by advances at HPCAT are expanding the range of materials investigated within CDAC. Many of these studies are a direct result of improvements in laser heating and resistive heating techniques45, as well as in situ high P-T Raman measurements with laser heating46. Several key results for phase relations and structures are representative of an increased effort toward advanced materials with special properties.

Phase Relations of H2O under Extreme Conditions – Furthering our understanding of H2O and other hydrogen-bonded systems impacts a broad range of problems, including detonation, aging, geophysics, life sciences, environment, and technology development. Last year, a Carnegie team used in situ high P-T Raman spectroscopy and synchrotron x-ray diffraction, to observe a triple point on the melting curve of H2O at approximately 35 GPa and 1040 K. The melting temperature of H2O increases significantly above the triple point28. Similar results obtained using high P-T Raman scattering and theoretical calculations were reported by CDAC collaborators from LLNL47,48. Previous synchrotron IR evidence for a low temperature transition found in ice VIII49 were confirmed by diffraction studies carried out at HPCAT that showed a structural transition near 14 GPa50. CDAC postdoctoral fellow Sergei Tkachev, Alexander Goncharov, and Russell J. Hemley (Carnegie) are studying the protonic diffusion in ice VII using Raman spectroscopy at high pressures and temperatures. The samples of H2O and D2O are loaded in the same cavity in the diamond anvil cell (DAC) using a double gasket technique. A preliminary study to 15 GPa and 573 K show a very small diffusion coefficient. Higher pressure studies approaching the P-T region of theoretically-predicted superionic phase of water are in progress.

Dissociation of H2O and Formation of a High-Pressure O2-H2 Alloy – Wendy Mao, a former CDAC graduate student now at LANL, together with Ho-kwang Mao, Jian Shu, Russell J. Hemley (Carnegie), Yue Meng, Michael Hu, Paul Chow (HPCAT), Peter Eng (University of Chicago) and Yong Q. Cai (National Synchrotron Radiation Research Center, Taiwan) carried out complementary measurements of H2O at higher pressures. A remarkable combined pressure and x-ray irradiation induced transformation in H2O was discovered. Mao and colleagues from Carnegie, HPCAT, and the University of Chicago cleaved H2O molecules, formed O-O and H-H bonds, and converted the O and H framework in ice VII into a new molecular alloy of O2 and H2. X-ray diffraction, x-ray Raman scattering and optical Raman spectroscopy demonstrated that this new crystalline solid differs from previously known phases (Fig 4). It displays surprising kinetic stability with respect to pressure, temperature, and further x-ray and laser exposure, thus opening new possibilities for studying molecular interactions in the fundamental O2-H2 system2. Carnegie summer high school student Alexander Levedahl (St. Anselm’s Abbey School) carried out follow-up up studies of the high P-T stability of the molecular alloy.

10 Figure 4. Left, Optical Raman spectra of irradiated sample at 17.6 GPa. Spectra of an un-irradiated ice VII sample at 17.1 GPa is shown for comparison; all measurements are based on the same exposure time. The Raman modes in the sample are excited

using Ar+ ion laser radiation at 488 nm. Right, photomicrographs of two DAC samples. Top four panels were taken at 13-IDC, APS, ANL. a) After XRS measurement at 13-IDC, APS, ANL at 8.8 GPa. The light brown streak through middle of sample shows portion irradiated by the x-ray beam. A small ruby ball on left the edge of gasket was used for pressure calibration. b) After release of pressure to below 1 GPa, bubbles of O2 and H2 formed. c) Bubbles collapsed upon increase of pressure as the H2 and O2 were incorporated into the crystalline sample. d) After XRS measurement at 15.3 GPa. Bottom two panels were taken at BL12XU, SPring-8. e) Sample before x-ray exposure at 2.6 GPa. f) After XRS measurement4.

Hydrogen under Extreme Conditions – There has been continued progress in the study of hydrogen under extreme conditions. Laser-heating/Raman scattering methods developed in CDAC collaborations have been extended, allowing the measurement of hot bands of the vibron at LLNL51 and further measured at Carnegie in hydrogen and other systems26. These important measurements constrain the intramolecular potential under extreme conditions. The effect of temperature on the pressure-dependent vibron coupling in resistively heating vibron measurements52 was examined53. High school student Andrew Kung (Winston Churchill HS, Potomac, MD) assisted in the development of resistive heating methods for hydrogen at high pressure. Kung measured the frequency of the H2 vibron at 20 GPa, from 300 to 500 K. Led by CDAC research scientist Chang-Sheng Zha, the work has led to improvements in resistive heating of compressed H2 that will be used in advancing the methods to higher pressures and temperatures. The experimental results have also been complemented by recent first-principles simulations carried out in CDAC54. Effect of Shear Stress on High P-T Transformations of Iron – Iron is one of the most abundant materials in our globe and dominates the Earth’s core. Thus the structural properties and the physics are important and critical for its application, as well as understanding the interior of the Earth. For the first time, Yanzhang Ma and the Texas Tech group explored the effect of shear stress and strain on the phase transition in iron from the bcc to the hcp phase using synchrotron x- ray diffraction measurements in a rotational DAC. Figure 5 (left) shows that the design of the cell allows rotation of the anvil on the piston side of piston-cylinder high-pressure apparatus. With the applied load firmly supporting the anvils, the rotation of the diamond anvil produces shear stress and strain on the sample and leads to strong plastic deformation. This, along with the fact that diamond is transparent to a wide range of frequencies, makes it possible to fully explore the properties of materials under high pressure and large shear. The group successfully utilized the rotational DAC in in situ x-ray diffraction measurements to study the effect of shear on the phase transformation, the lattice disorder, and transformation-induced plasticity of materials10.

11 Ma’s group has found that the initial transition is observed to take place at the reduced pressure of 10.8 GPa under pressure and shear operation, while a complete phase transformation was observed at 15.4 GPa. The rotation of an anvil causes limited pressure elevation and makes pressure symmetric in the sample chamber before the phase transition. It does, however, cause a significant pressure increase at the center of the sample and brings about a large pressure gradient during the phase transformation. The resistance to the phase interface motion is enhanced due to strain hardening during the pressure and shear operations on iron and this further increases the transition pressure. The work of macroscopic shear stress and the work of the pressure and shear stress at the defect tips account for the pressure reduction of the iron phase transition.

Figure 5. Left, schematic diagram of the rotational diamond anvil cell, showing the anvils, the sample chamber, and the alignment of x-ray beam for the in situ x-ray diffraction measurements. Right, x-ray diffraction patterns after the second compression operation and rotation of 180o at different positions along the diameter of the sample plate in comparison with pressure distribution at similar positions. The values marked on the diffraction patterns indicate the distance from the center, where the diffraction pattern was taken. The “-” and “+” signs respectively indicate the distances to the left and right side of sample center.

High Pressure X-ray Diffraction of Metal Sulfides – Metal dichalcogenides are excellent solid lubricants due to their graphitic structure and weak inter-layer bonding, which combine to facilitate shear when the direction of sliding is parallel to the planes. One of the typical metal dichalcogenides is tungsten disulfide (WS2), which can be either dispersed into liquid lubricants, like graphite, to reduce the friction and wear between moving surfaces; or used as a solid lubricant by itself. WS2 is an intrinsic solid lubricant and it functions effectively as a lubricant in air and inert gases as well as in high vacuum over a large temperature range. In the solid, the molecular units line up to form a hexagonal crystal structure in which the adjacent molecules along [001] direction interact through weak van der Waals forces (Fig. 6, left). The unit cell includes two adjacent layers and thus has hexagonal symmetry with a 2H arrangement. As part of the Ph.D. thesis project of Emre Selvi, the Texas Tech group, which also includes Yanzhang Ma, Resul Aksoy, Atila Ertas, and Allen White carried out high pressure synchrotron x-ray diffraction experiments to investigate the properties of WS2 to 26 GPa at room temperature. By fitting the P-V data to its EOS parameters, the bulk modulus was determined. The c-axis of the hexagonal structure is found to be much more compressible than the a-axis4 (Fig. 6, right).

12 Figure 6. Left, the crystal structure of WS2. The solid circles represent tungsten atoms, and the open circles represent sulfur atoms. Right, the ratio of the axial reduction with pressure for WS2.

Another disulfide, MoS2, has a crystal structure and applications similar to those of WS2. As part of his Ph.D. thesis project at Texas Tech, Resul Aksoy and his advisor and coauthors, Yanzhang Ma, Emre Selvi, Ming C. Chyu, Atila Ertas, and Allen White investigated the high- pressure behavior of MoS2, by synchrotron x-ray diffraction, to nearly 40 GPa at room temperature. The ratio of the compressibilities of the c-axis to the a-axis is approximately 3 at lower pressures (below 10 GPa). The ratio gradually decreases with increasing pressure with an apparent, phase transformation at high pressure and low temperature (Fig. 7)55. Elemental Structures – In high-pressure physics, Olga Figure 7. Pressure Degtyareva (former CDAC research dependence of the scientist, now at the University of unit cell volume of Edinburgh) and a group from MoS2 EOS to 20.5 GPa. Dashed line: Carnegie studied elemental sulfur, fit to second order selenium, tellurium, and arsenic and B-M EOS; solid found many high-pressures phases line: fit to third crystallized in novel chain or order B-M EOS. incommensurate structures56. Chalcogenic elements that are not superconductors at ambient pressure all become superconducting when compressed into body-centered orthorhombic (bco) and α-Po structures. Superconducting bco phase has an incommensurate structure, and the modulations decrease under pressure in the α-Po structure. The study clarified the problem of high-pressure sulfur structure and established the relationship between novel, high-pressure, crystal structures and superconductivity of the Group VI elements. Study of Ti21βS to 70 GPa – Ti21βS is a Ti alloy of importance to NNSA programs. High- pressure experiments were performed on Ti21βS, which forms nanometer-sized particles at high pressure, by Nenad Velisavljevic, Neal Chesnut, and Liliana Sanchez at LANL. X-ray diffraction data were collected to above 70 GPa. In the second experiment, it was possible to again

13 identify the Ti21βS bcc phase. Additional diffraction peaks were observed, however and it was possible to assign these to the hcp phase. The Ti21βS phase is therefore a mixture of bcc and hcp phases. The c/a ratio of this phase decreases from 1.60 at ambient conditions to 1.57 at 36 GPa, and then as pressure is increased to 44 GPa, the c/a ratio jumps back up to a value 1.61 and remains in this range up to the highest pressure. The change in c/a ratio at 40 GPa is interpreted in terms of a change in electronic structure, leading to stiffening of the lattice in one direction. Separate equations of state were fit for the bcc phase (Fig. 8) and the hcp phase of Ti21βS. In this pressure range (40 GPa), no structural phase change was observed. However, as the pressure is further increased, the peak intensities corresponding to the Ti21βS hcp phase start to decrease at and above ~58 GPa. High-Pressure Behavior of Quantum Dots – Kirill Zhuravlev, a postdoctoral associate working on Robert Sander’s group at LANL, has been comparing the high-pressure behavior of nanometer-sized PbSe quantum dots with the bulk material. With increasing pressure, bulk PbSe transforms from the NaCl structure into a new, apparently orthorhombic phase, consistent with the behavior of PbSe quantum dots. The high- pressure behavior of PbSe quantum dots is Figure 8. Ti21β S bcc data from both experiments found to also depend on the size of the dots. and the resulting EOS fit. Between 13.6 and 15.5 GPa, PbSe quantum

dots 12 nm in diameter transform to yet another high pressure, lower-symmetry phase (Fig. 9). Sharp volume discontinuities and hysteresis upon decompression of the PbSe samples indicate some intriguing behavior in the quantum dot phase. These aspects of the high-pressure behavior of this material are currently under investigation. High-Pressure X-ray Diffraction of Giant Dielectric Constant Materials – CaCu3Ti4O12 (CCTO) was recently found to exhibit an unusual dielectric performance, such that its dielectric constant can reach up to 105 at room temperature, while remaining independent of frequency and temperature in the DC range to 106 Hz, and from 100 to 600 K. Potential technical applications are anticipated in the electronic and medical technology industries, thus it is imperative to investigate the origin of such a giant dielectric constant. After intensive studies since the discovery of this effect in CCTO, many believe that it is due to an extrinsic mechanism such as the microstructure of ceramic or single Figure 9. X-ray diffraction patterns for 12 nmPbSe crystal samples rather than intrinsic quantum dots below and above the second phase transition. properties of the CCTO crystal. CCTO Arrows indicate the peaks present in one spectrum, but not exhibits remarkably strong nonlinear in the other.

14 current-voltage characteristics due to an intrinsic electrostatic barrier at the grain boundaries. Hence, it has been suggested that the giant dielectric constant could be caused by the creation of barrier layer capacitance, primarily at the twin boundaries or the interface between grains and grain boundaries or between sample and electrodes. In collaboration with Jianjun Liu of the University of Nebraska at Omaha, Yanzhang Ma led the Texas Tech group in measuring the high-pressure x-ray diffraction of CCTO under both hydrostatic and uniaxial compression. The cubic structure of CCTO is stable up to 57 GPa, but it was observed that CCTO has an unusual compression behavior under hydrostatic pressure. Specifically, the volume reduction is less than that under uniaxial compression below 25 GPa; above 25 GPa the volume reduction starts to approach and finally reach the same value as that under the uniaxial compression at about 30 GPa (Fig. 10, left). These remarkable phenomena are explained using a model in which the samples are composed of grains that have shells stiffer than the cores (Fig. 10, right)57.

Figure 10. Left, volume reduction under hydrostatic and uniaxial compression. Open circles, uniaxial compression; solid line, fitted results; solid square, hydrostatic compression. Error bar indicates the uncertainties in volume reduction. Inset (a), difference between volume reduction under at constant pressure for hydrostatic and uniaxial compression. Inset (b), difference between hydrostatic and uniaxial pressure needed to induce an equivalent volume reduction. In the insets, the horizontal dot-dash lines are reference lines showing no change. The vertical dot-dash line marks the midpoint of the volume change from its maximum to 0. The solid curves and the dotted lines are merely guides to the eye. Right, difference in work done on compressing CCTO under the same pressure with hydrostatic and uniaxial conditions.

Pressure Induced Phase Transitions in PbTiO3 – Lead titanate PbTiO3, one of the simplest ferroelectrics with the perovskite structure and the end member of a series of technologically important relaxor ferroelectrics, has been extensively studied by theoretical and experimental methods. In addition, PbTiO3 has not only played an important role in understanding the origins of ferroelectricity in perovskite-structured compounds but also in understanding the properties of relaxor ferroelectrics. Motivated by the need to understand the behavior of PbTiO3 at high pressure and low temperature, Muhetaer Ahart, in collaboration with others at Carnegie, has used x-ray diffraction and Raman spectroscopy to investigate single crystals of the material under hydrostatic pressure and from 20 K to room temperature. High pressure, low temperature (high-energy-high-resolution) x-ray diffraction was carried out at sector 11-ID-C of the APS. Figure 11 shows the pressure dependence of the positions of the [100] and [001] Bragg peaks between 5 and 15 GPa at 10 K. The results are consistent with the predictions from first principles calculations. Monoclinic phases were also found in other relaxor ferroelectric solid solutions at ambient pressure. This result shows that the large strain piezoelectricity in solid solutions of PbTiO3 arises from the behavior of the parent material itself, while the other components tune the transition pressure.

15 Raman bands of PbTiO3 show dramatic changes around 20 GPa at 20 K. Most importantly the number of higher frequency bands is doubled, indicating a zone boundary instability in PbTiO3. Based on the experimental results and recent theoretical calculations, a good candidate for the symmetry of PT above 20 GPa would be rhombohedral. In this nonpolar structure the distortion from the cubic structure is due to antiphase rotations of the oxygen octahedral around the [111] direction, which result from the condensation of zone-boundary modes (R25), thus doubling the unit cell. Splitting of the A1 and E modes above 20 GPa at 20 K is related to the zone boundary instability-induced phase transition. New Properties of Dense Oxides and Silicates – Following the synthesis of the post- perovskite phase in MgSiO3, former CDAC graduate student Wendy Mao (LANL) and colleagues from Figure 11. Pressure dependence of Bragg Carnegie, ANL, and the University of Chicago peak position [100] and [001] (left) and sought to address the question of whether Fe can play a lattice parameter (right) in a single major role in this phase as the core-mantle boundary crystal of PbTiO3. The [111] Bragg peak shows obvious splitting at 14 GPa at 10 (CMB) represents the region where the silicate mantle K. This is consistent with the monoclinic is in contact with the liquid, Fe-rich outer core. They distortion predicted theoretically5. conducted a number of DAC synchrotron x-ray experiments at the very challenging ultrahigh P-Ts of the CMB that demonstrate that this phase can incorporate a considerable amount of the Fe which leads to large increases in density relative to MgSiO3 post-perovskite58, 59. The vast reservoirs of liquid Fe and Fe-poor silicates at the CMB provide favorable chemical-physical conditions for the formation of Fe-rich post-perovskite silicate which may hold the key to understanding the geophysical and geochemical properties of the CMB (Fig. 12). The group has subsequently reported a major new finding in high-pressure geophysics. The work focuses on iron-rich post-perovskites and the ultralow-velocity zones. The boundary layer between the crystalline silicate lower mantle and the liquid iron core contains regions with ultralow seismic velocities. Such low compressional and shear wave velocities and high Poisson’s ratio are also observed experimentally in a post-perovskite silicate phase containing up to 40 mol% FeSiO3 endmember. The iron-rich post-perovskite silicate is stable at the P-T and chemical environment of the CMB and can be formed by core-mantle reaction. Mantle dynamics may lead to further accumulation of this material into the ultralow-velocity patches that are observable by seismology60.

Figure 12. Left: schematic diagram of the reaction boundary between a Fe-poor mantle and Fe-rich core and the accumulation of Fe-rich post-perovskite in ULVZ. Right: X-ray diffraction pattern for Fs40 post- perovskite at 138 GPa (λ=0.3344 Å).

16 Using nuclear resonant inelastic x-ray scattering coupled with EOS measurements the team was able to determine aggregate sound velocities for a post-perovskite composed of 40% of the Fe endmember, i.e. (Mg0.6Fe0.4)SiO3. The determined compressional and shear wave velocities indicate that post-perovskite with Fe can reproduce the dramatic depression in seismic velocities in ultralow velocity zones (ULVZ)—i.e. thin 5-40 km thick patches of depressed compressional and shear wave velocities (decreases of ~10 and ~30% relative respectively to PREM) observed just above the CMB - providing an alternative explanation for the origin of ULVZ60. Although further studies of post- perovskite as a function of temperature and Fe concentration are still needed, these results provide an exciting new direction into the dominating role Fe-rich post-perovskite may play at the CMB. High-Pressure Perovskites – CDAC graduate student Claire Runge (Princeton) carried out a detailed study of MgGeO3 perovskite to determine how its properties compare with those of the MgSiO3 post-perovskite phase. Minerals adopting the perovskite structure are the dominant phases in the Earth's lower mantle. The perovskite structure also is adopted by a wide range of inorganic compounds, many of which have technological applications as ferroelectrics and superconductors. Germanates have been used extensively as low-pressure analogs for silicates as they undergo similar phase transition sequences at lower pressures.

Using synchrotron x-ray diffraction and the laser-heated DAC the EOS of MgGeO3 perovskite was determined between 25-66 GPa (Fig. 13). The EOS and structural parameters were also calculated using density functional theory. Comparison with previous work on the post- perovskite phase61 allowed the Princeton group to determine that the density increased by 2.0(0.7)% across the transition. The bulk sound velocity change across the transition is small and is likely to be negative (-0.5(1.6)% from experiment and -1.2% from theory). These results are similar to previous findings for the (Mg,Fe)SiO3 system62. Germanate and silicate perovskites also show similar trends in axial compressibilities although germanates show more anisotropy than silicates. As one example of its application as an analog material, deformation studies on MgGeO3 post- perovskite have been used to infer slip systems relevant to understanding deformation and seismic anisotropy in the deep mantle14. The results obtained by the group provide support for the concept that germanates may be suitable analogs for the mechanical behavior of silicates at high pressures.

Figure 13. Comparison of experimental pressure-volume measurements for MgGeO3 perovskite and post-perovskite phases. Solid circles, perovskite data (this study); open circles, post perovskite data60. Solid and dashed curves are fits using 3rd order Birch-Murnaghan EOS for the perovskite and post- perovskite data, respectively.

Carnegie Postdoctoral Fellow Pierre Beck, along with Alexander Goncharov and Russell J. Hemley is currently studying a San Carlos olivine under high P-T conditions using Raman spectroscopy. In these studies, the sample is pressed in an Ir ribbon, which serves as a laser absorber, and Ar serves as both pressure medium and thermal insulator, while the temperature achieved upon heating by a YLF laser are measured through radiometry. Spectra acquired at 9 and 13 GPa to 2000 K show the expected softening and broadening of the observed Raman active modes. For temperatures above 1800 K the transition to the β-phase is observed. The absence of any γ-phase

17 rules out the presence of a significantly high thermal pressure (<2 GPa). The phase transition appears to be reversible upon cooling.

High Pressure X-ray Diffraction of ThSiO4 and HfSiO4 – Kimberly Tait, a graduate student of Robert Downs at the University of Arizona working at LANL has carried out a series of high-pressure studies of zircon (ZrSiO4), hafnon (HfSiO4), and thorite (ThSiO4). These three minerals that crystallize in the space group I41/amd and all occur naturally in the earth’s crust during the later stages of magmatic activity. Minerals with the zircon-type structure show wide chemical stability and are among several crystalline phases under consideration for the immobilization and disposal of high-actinide radioactive wastes63. Natural samples of these minerals tend to be partly metamict due to the presence of these radioactive elements in their structures and have compositional substitutions among the cations, which tend to make them poor candidates for x-ray diffraction studies. Previous shock experiments64, 65 and DAC experiments66-68 show that zircon undergoes a phase transition at high pressures and temperatures. The high- pressure phase is a scheelite-type structure (I41/a) named reidite69 to which zircon transforms at 20 GPa68. Although several x-ray diffraction and Raman spectroscopy experiments have been performed on zircon, there was no information about the high pressure phases of thorite and hafnon, nor was there any systematic study of their equations of state. ThSiO4 has a polymorph, huttonite (monoclinic P21/n); the low-density, high-symmetry thorite transforms to huttonite (lower-symmetry, higher density) at ~1200oC70. This is contrary to the general expectation based on a comparison to lanthanide orthophosphates- the low temperature polymorphs have a monzanite (monoclinic) structure and the high-temperature polymorphs have the zircon (tetragonal) structure71. No such high temperature studies had been documented in the literature for hafnon. Besides the anomalous phase transformations for ThSiO4, the molar volume of thorite is higher than that of huttonite, which would suggest that huttonite should be more stable at higher pressure.

Tait used a hafnon sample that was grown in a platinum crucible from a Li2MoO4 melt which was about 5% by weight HfO2 · SiO272. A new sol-gel hydrothermal synthetic technique has also been developed and will be used in future work on thorite. This synthesis technique has been perfected over a considerable amount of time and there is no unreacted ThO2 in the final sample. Data were collected to 48 GPa at the HPCAT 16-ID-B beamline, using approximately 5 GPa pressure steps to determine the bulk modulus and characterize the high pressure phases of hafnon. At approximately 27 GPa hafnon undergoes a phase transition to the previously undetermined scheelite-type structure (I41/a), which was predicted due to the zircon-reidite phase transition, but no further phase transitions were observed. Tait studied thorite, which is radioactive and had to be loaded at LANL and shipped via the requirements of the APS. The sample was well crystalline but at 12 GPa the sample peaks became weak and appeared to become amorphous, which might be due to a chemical reaction with the pressure medium, or due to perhaps particle size effects arising from the synthesis conditions. Further high pressure Raman work is being carried out in coordination with the University of Arizona. Melting and Phase Relations in the Fe-FeO System – The Heinz group at the University of Chicago has collected extensive data on the melting and phase relations in the Fe- FeO system from 18 to 136 GPa spanning bulk compositions from 5 to 90 weight % FeO. They have shown that the system is not a solid solution as some had predicted73 up to at least the core – mantle boundary. This is an important result; since the melting temperature of FeO at the Earth’s core mantle boundary is significantly greater then the melting temperature of pure Fe 73, 74, a complete solid solution would be incompatible with the energy requirements of the geodynamo. The eutectic temperature was bound in this system using the same method used in the Fe-Fe3S system. The eutectic temperature rises rapidly closely following the melting curve of pure Fe up to 96 GPa, and thus there is not a significant melting point depression with respect to pure Fe. The nature of studying binary phase diagrams with x-ray diffraction naturally allows the simultaneous determination of the end-members. Thus this group has very precise densities of the co-existing phases that will allow a calculation of the maximum allowable oxygen content of the outer core,

18 allow an EOS calibration of FeO, and provide information on the iron-wüstite buffer at high pressures and temperatures. 2.2 P-V-T EOS Measurements The P-V-T EOS is one of the most basic pieces of information needed for predicting material behavior and validating codes that are crucial to stockpile stewardship science. A broad range of techniques at CDAC are used and further refined for these experiments. These methods include x- ray and neutron diffraction studies of crystalline and non crystalline materials, including polymers, as well as sound velocity measurements using high-pressure Brillouin scattering and ultrasonic techniques. These experiments complement dynamic compression studies. The EOS of low-Z materials,75-78 provide a critical baseline required for understanding the kinetics, thermal transport, and other important properties of detonation and other chemical processes30, 75, 76, 78. Combined density functional theory molecular dynamics and path-integral Monte Carlo simulations have shown that many-body effects are extremely important in describing the observed phenomena even in these apparently simple systems79, 80. Megabar Diffraction of Be – Beryllium is an important material in nuclear science and technology. CDAC made possible beam time for LLNL scientists to carry out angle-dispersive x-ray diffraction studies of simple materials. Led by Will Evans and Choong-shik Yoo, the group includes graduate students Zsolt Jenei and Amy Lazicki, who have studied the high-pressure behavior and EOS of beryllium, an important material for the nuclear power industry and a broad range of advanced technologies such as aerospace, alloys, x-ray windows. Be is an anomalous metal because of its unusual physical properties, but it is also one of the simplest metals with only four electrons per atom. Thus studies of Be are also of basic scientific interest as a model system for developing predictive theoretical models. The group has studied the crystal structure and determined the EOS of Be up to pressures approaching 200 GPa, an important technical achievement made possible by the facilities available at HPCAT. Low-Z Compounds – CDAC supports facilities used by students working with other groups in the SSAAP program. University of California – Davis graduate student Amy Lazicki, along with a group from UC-Davis, HPCAT, and LLNL, found a remarkable stability of the N3- ion in Li3N to a sixfold volume reduction81. A new (γ) phase is discovered above 40(±5) GPa, with an 8% volume collapse and a band gap quadrupling at the transition determined by synchrotron x-ray diffraction and inelastic x-ray scattering. γ-Li3N (Fm3m, Li3Bi-like structure) remains stable up to 200 GPa, and calculations do not predict metallization until 8 TPa. The work has been done in collaboration with the theoreticians Warren Pickett and Richard Scalettar; the group has also studied phase transitions in Li2O. Sung Keun Lee (formerly of Carnegie, now at Seoul National University) and colleagues from the University of Chicago (Peter Eng and Matthew Newville), HPCAT (Michael Hu and Yue Meng), and Carnegie (Jinfu Shu and Ho-kwang Mao) studied the near K- edge structures of boron and oxygen of v-B2O3 glass to 22.5 GPa, revealing pressure-induced bonding changes. Direct in situ measurements show a continuous transformation from tri-coordinated to tetra-coordinated boron beginning at 4-7 GPa, forming dense tetrahedral v-B2O3. After decompression from high pressure the bonding reverts back to tri-coordinated boron but with the data suggesting a permanent densification82. Polymers – Polymers and their composites play important roles in DOE and DOD munitions applications, including in high explosives (as binders), structural materials, and armor. However, many currently employed material models used in modeling and describing their behavior are overly simplified, and are not constructed based on polymer physics and associated molecular level insights. The goal of this work is to provide improved experimental input into these models for a variety of polymeric materials. The complexity of polymers, including their multiphase structure, possible presence of filler materials, and rate and temperature dependent behavior, requires the application of multiple experimental techniques to fully capture their behavior, particularly under high P-T

19 conditions, including dynamic loading scenarios. Dana Dattlebaum and colleagues at LANL are employing multiple approaches to the construction of EOS functions for these materials, including piston-cylinder measurements, Brillouin scattering, x-ray diffraction, vibrational spectroscopy, plate impact experiments, and positron annihilation lifetime spectroscopy. This group has completed measurements on poly(tetrafluoroethylene) (PTFE) at HPCAT, measuring x-ray diffraction as a function of pressure. PTFE has at least four known phases near ambient temperature and pressure. The dynamic mechanical behavior of PTFE is highly influenced by the crystalline phase transitions. They have collected high fidelity diffraction patterns to confirm the known phase behavior of PTFE, and extracted pressure-volume relationships to 10 GPa. In doing so (and with the aid of Raman spectroscopy results), they have also discovered a new phase “V” at pressures > 5 GPa in PTFE (Fig. 14)7. They have extended their measurements to examine the phase behavior in the related fluoropolymers poly(chloro-trifluoroethylene) (PCTFE), poly(chloro- trifluoroethylene-co-vinylidene fluoride) (Kel-F 800), and poly(tetrafluoroethylene-co- hexafluoropropylene-co-vinylidene fluoride) (THV 500). So far (to 14 GPa), despite similar molecular structures, the crystalline domains associated with these polymers do not appear to undergo any crystalline phase transitions. These findings will ultimately be linked to the mechanical properties of these polymers, particularly in comparison to the behavior of PTFE. The brightness of the source at APS resulting in high quality diffraction patterns may allow us to eventually extract P-V data from the presumed triclinic (helical) structure. Certain polymer materials of interest do not contain any crystalline content. In order to acquire EOS data on these materials, the group has pursued piston-cylinder pressure-volume measurements, optical microscopy (giving stiffened compression curves)9, and impulse stimulated light scattering. In collaboration with Muhetaer Ahart and Russell Hemley at Carnegie, Dattlebaum’s group at LANL have recently initiated Brillouin scattering measurements on three amorphous, and low crystalline content polymers: a crosslinked poly(dimethylsiloxane) material (Sylgard® 184), a polyethylene terpolymer, and a polyester- urethane co-polymer. The sound speeds for Figure 14. X-ray diffraction pattern of PTFE at 3.5 GPa and 6.3 GPa. these three distinct polymer systems have been measured from ambient pressure to approximately 12 GPa in DACs using Brillouin scattering (Fig. 15). These results appear to be the first comprehensive Brillouin scattering results on polymers at high pressure. With the exception of Sylgard® 184, both transverse and longitudinal acoustic modes were observed for at slightly elevated pressures and above for all the polymers. For these materials, P-V isotherms were constructed from the Brillouin-scattering data and fit to a range of empirical/semi-empirical EOS. From this analysis the isothermal bulk modulus and its pressure derivative were obtained. Besides the EOS, mechanical properties were also analyzed in relation to the second order elastic constants and Poisson’s ratios8. Finally, the group initiated new experiments on the high explosive material tri-amino-tri- nitrobenzene (TATB). They are working to extend the known isothermal compression curve for TATB using high pressure powder diffraction at HPCAT and anticipate that this work will continue into the next year.

20 Figure 15. Left: representative Brillouin spectra at various pressures (in GPa) of Sylgard® 184. The longitudinal modes are seen on either side of the intense Rayleigh line. Right: pressure dependence of the longitudinal (L mode) and transverse (T-mode) sound velocities for polymers measured in this study.

EOS of Gelatin – Gelatin is one of the most versatile hydrocolloids, and has a wide variety of uses, including as a model of human tissues. At Carnegie, a team led by Muhetaer Ahart is using Brillouin scattering techniques to obtain the EOS of gelatin. The Brillouin scattering experiments are carried out from ambient pressure to 12 GPa from 0 to 100 °C. Figure 16 (left) shows a typical Brillouin spectrum at 3.23 GPa at 25 °C. The Rayleigh scattering line (elastic scattering) at the zero frequency as well as the Brillouin scattering lines (inelastic scattering) at around 6 GHz for transverse acoustic mode and at around 14 GHz for longitudinal acoustic mode are observed. The sound velocity at any given pressure is a direct measure of the pressure, and so accurate P-V data are possible (Fig. 16, right).

Figure 16. Left: a representative Brillouin spectrum of gelatin at 3.23 GPa. The strong line at zero frequency is the Rayleigh scattering line, L- and T-mode represent the longitudinal and transverse acoustic modes, respectively. Right: Pressure dependence of density of gelatin. The open circles represent the experimentally obtained density and the solid line represents the Vinet EOS fit. (Ko = 7.6 GPa and Ko’ = 13.98.

Binary Iron-Light Element Systems at High Pressure – Dion Heinz and his group at the University of Chicago have studied binary iron-light element systems at high pressure, in particular the Fe-Fe3S and Fe-FeO systems. A manuscript on the thermal EOS of Fe3S was published this year83 and a manuscript detailing melting in the Fe-Fe3S system has been submitted84. The group determined the eutectic temperature in the Fe – Fe3S system up to 60 GPa and placed a lower bound at 80 GPa. Comparison with their Fe-Fe3S melting data with the melting curve of pure Fe85, 86 indicates that the melting point depression of Fe, due to sulfur alloying in the

21 melt, amounts to 600-800 K over the pressure range of this study (30 to 80 GPa). The Heinz group’s melting point depression of 600-800 K is identical to that calculated by ab initio methods87, for a Fe- S-O melt at 330 GPa, the pressure of the inner core / outer core boundary. Most estimates of pure Fe melting at this pressure are in the range 5300-6700 K87, 88; applying a ~700 K melting point depression to this range implies a minimum inner core / outer core boundary temperature of 4600- 6000 K. The Chicago group has also studied stoichiometric FeS (troilite) up to 80 GPa with the laser heated DAC and x-ray diffraction. Troilite undergoes a series of phase transitions with increasing pressure and temperature that may be important for interpretation of future Martian seismic data. They have determined the P-T boundary of the FeS (IV) and FeS (V) polymorphs, data at higher pressures indicate another possible phase transition and they are currently working on the structure. Reflectivity of Iron at High Pressure – The Heinz group at the University of Chicago has also collected some reflectivity data for iron at high pressure at NSLS beamline U2A. One of the biggest sources of error for temperature measurement using the spectroradiometric method is the sample emissivity (both magnitude and wavelength dependence). Reflectivity measurements were made on an iron foil and powder up to 50 GPa at ambient temperature in an attempt to estimate the spectral emissivity of iron. Some of this data looks good, but a complete analysis has been difficult due to an unexpected non-linear relation between beam current and intensity. The group is still trying to figure out the best way to account for this. Even though it has been difficult to determine the absolute magnitude of the reflectivity it is apparent that the slope of the reflectivity decreases with pressure indicating that the grey body approximation becomes a better approximation at higher pressures and ambient temperature. Accurate P-T Calibration – Pressure determination is central to all high-pressure experiments. The commonly used ruby fluorescence pressure scale has high intrinsic precision (±0.5% in pressure under hydrostatic conditions above 20 GPa) but uncertain accuracy (±5%) because it is a secondary scale calibrated by less precise (±5%) primary standards deduced from high- temperature shock-wave data on metals89, 90. Efforts are being made among the high-pressure community to develop pressure scales at high temperature91. The Carnegie and Princeton groups are extending such calibrations to >1000 K with the integrated Brillouin and x-ray method. Yingwei Fei and colleagues92 continue to extend x-ray calibration to high P-T conditions. Additional studies have been carried out in collaboration between LLNL and Carnegie42. 2.3 Phonons, Vibrational Thermodynamics, and Elasticity The study of phonon dynamics in highly compressed materials is crucial for understanding thermodynamic properties, elasticity, and phase transition mechanisms. To this end, measurements of the elastic tensor provide information on elastic wave propagation, mechanical stability, interatomic interactions, material strength, and phase transition mechanisms. HPCAT and LANL have provided capabilities, to advance the state of the art in phonon experiments. Gigahertz ultrasonic interferometry and Brillouin spectroscopy serve as additional important tools for elucidating fundamental elastic properties of materials. Effects of Vacancies on the Phonons in FeAl at High Pressure – Brent Fultz’s group at Caltech began research on FeAl. The most interesting results were obtained from very recent high pressure measurements on samples of FeAl that were quenched from different high temperatures to preserve a vacancy concentration as high as 3%. Compared to the control sample, the sample with excess vacancies was known to have a broadening and stiffening of the phonon partial DOS of 57Fe. (This was consistent with prior work with inelastic neutron scattering.)This effect of vacancies becomes significantly larger at higher pressures (Fig. 17). The trend is clearly a systematic one, as are the stiffenings of the phonons in each material with increasing pressure. The vacancies in FeAl alter characteristic interatomic forces, changing the anharmonicity, expressed as a larger Grüneisen parameter. Further interpretations of the results are underway using a lattice

22 dynamics inversion method, where the interatomic forces are tuned to match the measured scattering or phonon partial DOS curves (Fig. 17). The goal is to identify which force constants undergo the largest stiffening in the presence of vacancies. New neutron inelastic scattering experiments on FeAl were performed with the LRMECS chopper spectrometer at the Intense Pulsed Neutron Source at Argonne National Laboratory. These measurements were superior to the group’s previous measurements because they used a new furnace for in-situ measurements that had a much lower background, and produced higher-quality data than previous work with the PHAROS instrument at LANL. The group plans to modify the present furnace to reach temperatures of 700° C or so, and try the measurements once again on LRMECS in the Fall of 2006. Density functional computations on FeAl were begun in conjunction with the PHONON software Figure 17. 57Fe phonon partial DOS package of K. Parlinski. Computations for different curves obtained by INXRS. Two samples volumes of the cubic unit cell show phonon stiffening were used, one quenched from 1273 K containing an estimated 3% vacancies consistent with the experimental results on the (red), and the other quenched from 773 K, material without vacancies. This work will continue containing less than 0.5% vacancies in Year 4. (black). Measurements were performed at Cluster Expansions of Phonon DOS – To a series of pressures matched to within approximately 0.3 GPa. date, alloy free energies, phase diagrams and equations of state have been successfully interpreted in terms of the thermodynamics of local atom configurations. Cluster expansion hierarchy can be performed systematically, and it is often found that most of the configurational thermodynamics depends on the statistical numbers of pairs of atoms of the different chemical species in an alloy. An open question is how successful will be this cluster expansion method in accounting for the phonon entropy. The Fultz group at Caltech has also explored the effects of local order on the 57Fe partial density of states (pDOS) in alloys and thin films of FeCr using inelastic nuclear resonant scattering (INRXS) at HPCAT. A cluster expansion of the alloy pDOSs was used to determine the basis and structure that most accurately represents the thin film multilayer results published previously by Ruckert, Keune, Sturhahn, et al.93. The alloys used in this cluster expansion were shown to be suitable by fitting to thin film multilayers. The thin film multilayer pDOSs constructed using pair clusters of first- and second-nearest-neighbors were found to be very similar to the pDOSs from the thin-film results. The contribution to the 57Fe pDOSs from each of the terms in the cluster expansion was determined, showing the effects of local order on the pDOSs explicitly. Evidence of strong magnetoelastic effects was seen in the energy range of 20-25 meV, consistent with dispersion curves in the literature. A manuscript is in preparation for Physical Review B and the work is part of the Ph.D. thesis of CDAC student Matthew S. Lucas94. Elastic Tensor of Alunite – In a collaboration between Tom Duffy’s group at Princeton, CDAC-affiliated postdoctoral associate Sergio Speziale (Berkeley), and Juraj Majzlan (Freiburg), determined the single-crystal elastic constants of alunite (KAl3(SO4)2(OH)6) by Brillouin spectroscopy. Alunite and related Fe-Al sulfates attract attention because they are associated with acid mine drainage, a widely recognized environmental problem. There is also increasing interest in sulfates as important components of planetary surfaces, for example on Europa or Mars. Characterization of the elastic properties of hydrous sulfates is an important step in constraining the

23 overall thermodynamics of these phases. Brillouin experiments were performed to give elastic constants (in GPa) C11 = 181.9 ± 0.3, C33 = 66.8 ± 0.8, C44 = 42.8 ± 0.2, C12 = 48.2 ± 0.5, C13 = 27.1 ± 1.0, C14 = 5.4 ± 0.5. The Voigt-Reuss-Hill average of bulk and shear moduli are 62.6 and 49.4 GPa, respectively. The Poisson ratio and the elastic Debye temperature are 0.19 and 654 K, respectively. The high value of the ratio C11/C33 = 2.7 and the large discrepancy between the elastic and heat capacity Debye temperature are characteristic of the anisotropic structure of alunite. Elastic Properties of Hydrous Materials – Hydrous minerals in subduction zones are potential agents for transporting water to the deep Earth. Properties of these minerals, especially elastic moduli, are needed to model seismic wave speeds in subduction zones and hence place constraints on cycling of H2O through subduction zones. Zoisite is a metamorphic mineral of the epidote group containing 2 wt % water. It is likely to be one of the important phases in subduction zone environments. In this study, the single-crystal elastic constants of zoisite Ca2Al3Si3O12(OH) were determined by CDAC graduate student Zhu Mao (Princeton) using Brillouin scattering at ambient conditions. Brillouin spectra were recorded in 37 directions for three separate crystal planes. The density of the sample and the orientation of each plane were determined by single- crystal diffraction using energy dispersive techniques at X17C of the NSLS. The complete elastic tensor was then obtained by an inversion of the acoustic velocity and orientation data. The Voigt- Reuss-Hill averages of the aggregate bulk modulus, shear modulus and Poisson’s ratio were determined. These results resolve discrepancies in previous static compression studies and provide the first determination of the shear modulus of zoisite. Elastic Properties of Oxide Spinels – In collaboration with Hans Reichmann (Geoforshungzentrum Potsdam), Steve Jacobsen (formerly of Carnegie, now at Northwestern University) used GHz-ultrasonic interferometry to probe the high-pressure elastic properties of dense oxide spinels with general formula AB2O4. Because of their abundance in the Earth and ubiquity in materials science as magnetic and superconducting materials, spinel- structured phases are among the most well-studied materials both theoretically and experimentally. Well over 100 natural and synthetic phases adopt this structure. However, the single-crystal elastic constants of many spinels, especially those containing transition metal elements, are unknown because they are optically opaque to light-scattering techniques. The complete elastic tensor of magnetite (Fe3O4) and the zinc-aluminate spinel (ZnAl2O4, ghanite) has been determined to 10 GPa using GHz-ultrasonic interferometry95, 96. In addition, sound velocities and elastic constants have been determined for the silicate spinel (Mg,Fe)2SiO4 (ringwoodite)97, thought to be the dominant phase in the transition zone region of Earth's mantle (410-660 km depth). Trends indicate that spinels containing transition metals on both the A and B sites follow different elasticity systematics than those without any, or only one transition metal (Fig. 18).

Figure 18. Plot of Birch's Law for spinel- structured phases. GHz-ultrasonic interferometry has been used to determine the bulk sound velocity (Vφ) of several dark or opaque spinel phases including γ-(MgFe)2SiO4 (ringwoodite), gahnite, magnetite, and fanklinite. Trends indicate that those spinels with transition metals on both the A and B sites of AB2O4 follow a trend 5-times more negative than those without any or only one transition metal94.

For this work at Carnegie, Jacobsen set up the only GHz-ultrasonic interferometry laboratory in the US. This novel acoustic technique is being used to probe the elastic properties of microscopic samples at high-pressures in the DAC. The instrument measures compressional and

24 shear-wave travel times through parallel-polished platelets as thin as 20-30 µm thickness. By operating at 0.5 to 3 GHz, travel times down to 10-15 nanoseconds can be measured interferometrically with a precision of a few tens of picoseconds. The technique is ideally suited for determining the single-crystal elastic constants of opaque materials not suitable for light-scattering methods. Short acoustic wavelengths (5-10 µm at 1-2 GHz) allow very small high-pressure samples to be studied24. Jacobsen moved to Northwestern University as an Assistant Professor in September 2006, where he will continue to collaborate with CDAC projects. Texture Development at High Pressure – The core of the Berkeley contribution to CDAC is to study the influence of non-hydrostatic stress on crystals and polycrystals, particularly at high and ultrahigh pressure and temperature, and to investigate the effects on anisotropic physical properties. Anisotropy in polycrystals is largely determined by preferred orientation (texture), which evolves during deformation and is modified during recrystallization and phase transformations. To this end Rudy Wenk’s group has been developing synchrotron diffraction techniques, particularly those involving the DAC in the radial geometry and multianvil systems. The group has also been active in applying time-of-flight neutron diffraction techniques to texture problems. The experimental data are in the form of 2D diffraction images and 1D diffraction spectra. New methods, based on the Rietveld procedure, have been developed to extract quantitative information about texture and stress. Overall, the group has used a variety of experimental user facilities in this work, including synchrotron x-ray facilities12, 44, 98-102. Some of the research has involved improving experimental techniques (e.g. DAC gasket technology, neutron furnaces) and data processing. A breakthrough has been the capability of obtaining quantitative texture information from single diffraction images, without imposing sample symmetry. Also the group was able to document strain distribution in the DAC. Gasket technology was greatly improved by changing from a boron-epoxy gasket that produced high background to a small boron-epoxy ring, surrounded by kapton. Graduate student Lowell Miyagi (Berkeley)has carried out systematic investigations of texture development in MgSiO3 perovskite, and has found that the material displays different texture types depending on synthesis conditions and starting material. So far he has been able to document a 100 texture (transforming from ringwoodite), a 012 texture (transforming from olivine) and a 001 texture (transforming from enstatite). Furthermore the texture changes with time (at constant pressure) and also during heating (recrystallization). Recently a strong texture has been observed in Ge-post-perovskite and Si-post-perovskite. The 110 texture is compatible with [001] pencil glide which makes sense since [001] is the direction of the octahedral chains in the structure. Recently group members had the opportunity to perform experiments with the D-DIA apparatus at APS and produced a strong (010) texture, distinctly different from the (100) texture observed in the Si and Ge post-perovskites. D-DIA experiments on analogs (including CaGeO3 perovskite) provide an excellent complement to diamond anvil experiments14, 103. Graduate student Jenny Pehl (Berkeley) has used these neutron diffraction techniques to reveal the fact that textures that develop during deformation have profound implications for seismic anisotropy in the earth. She has been able to use information about microscopic mechanisms gained from DAC experiments to simulate macroscopic anisotropy development in the lower mantle and found that perovskite texture alone can explain the observed seismic anisotropy near the CMB Texture changes during phase transformations further confirmed a strong variant selection in many systems (Fe, Zr, Ti and most dramatically in quartz). This is attributed to intercrystalline stresses that develop, in quartz perhaps associated with mechanical Dauphine twinning that may become a useful paleopiezometer for tectonic as well as shock stresses. An exciting new area of research has been the in situ observation of stress distributions during straining with the high resolution engineering neutron diffractometers ENGIN-X and SMARTS104.

25 2.4 Plasticity, Yield Strength, and Deformation

Understanding the behavior of key materials at high plastic strain (εP > 100%), and high strain rates (up to 105) is crucial for science-based stockpile stewardship. The texture provides data for interpreting active deformation mechanisms, and phase transformations induced by pressure and temperature produce systematic changes in texture patterns. The new work in CDAC builds on the semi-empirical modeling techniques developed to extract elasticity information from the x-ray and neutron diffraction studies on textured polycrystals105-110. The focus of much of this work is the influence of non-hydrostatic stress on crystals and polycrystals, particularly at high and ultrahigh pressure, and to investigate the effects on anisotropic physical properties. The anisotropy in polycrystals is largely determined by preferred orientation (texture) and how texture evolves during deformation and is modified during recrystallization and phase transformations. Experimental data have been applied to extract quantitative information about texture and stress. Plastic Behavior of Post-Perovskite Deep in the Earth's Interior – Sebastien Merkel and colleagues from Berkeley, Princeton, and Carnegie reported direct measurements of the plastic behavior of post-perovskite deep in the Earth's interior. Under the pressures of the CMB (2900 km below the surface), the main constituent of the deep mantle, silicate perovskite, undergoes a phase transition to a post-perovskite phase whose mechanical properties remain unknown. Merkel's team monitored the development of lattice preferred orientation in an analogue of silicate post-perovskite plastically deformed above 100 GPa. The experiments were carried out inside a diamond anvil pressure cell and the measurements performed using x-ray diffraction at HPCAT (Fig. 19). From these measurements, it was discovered that (100) and (110) slip dominate the plastic deformation of post-perovskite. The CMB is a critical region for the Earth's dynamics and seismologists have long documented anisotropy at these depths. Seismic anisotropy is the expression of deformation and dynamics and with the measurement capabilities developed as a result of this research, it can now be interpreted. Moreover, the application of this experimental technique is not limited to geophysics and it can now be extended to improve our understanding of the plastic behavior of a whole array of materials under extreme conditions of pressure, stress, and temperature14.

Figure 19. Contribution of silicate post-perovskite to seismic anisotropy in D” after 20% deformation in shear. Left: crystal structure of CaIrO3-type silicate post-perovskite. Upper right: anisotropy of compressional (Vp) and shear (Vs) wave velocities determined from texture analysis of x-ray diffraction data. Lower right: model derived from diffraction data depicting the participation of MgSiO3 post-perovskite in lower mantle and D’’ dynamics, leading to anisotropy in sound velocities. The model predicts simple shear parallel to the CMB.

26 Synergy Between Static and Dynamic Compression and Theory – Combined shock and dynamic experiments provide the opportunity for advances in understanding ultrahigh P-T rheological behavior. SiC is an example of a material whose strength, elastic, and optical properties have attracted strong interest from both shock-wave and static compression communities111-113. The fabrication of large single crystal CVD diamond at Carnegie has led to an LDRD project at SNL to study the elastic-plastic response of diamond on dynamic compression. Related studies of interfaces and cracks under pressure were investigated in Year 3 with the picosecond vibrational SFG technique in Dana Dlott's lab at Illinois. 2.5 Electronic and Magnetic Structure and Dynamics Understanding the complex interplay of electronic and magnetic structure is fundamental to many problems associated with stockpile stewardship science.

Bonding and Electronic Structure of H2O – A LLNL group, consisting of Choong-shik Yoo, Will Evans, Hyunchae Cynn, Magnus Lipp, and graduate students Amy Lazicki and Zsolt Jenei have carried out inelastic x-ray scattering (x-ray Raman) spectroscopy of high-pressure phases of water, in collaboration with Paul Chow and Michael Hu at HPCAT. These studies are aimed at addressing controversies regarding the high-pressure properties of water and build on techniques also used by the Carnegie team at HPCAT2, 114. The technique provides data that is equivalent to x-ray absorption, but utilizes a hard x-ray to avoid absorption by diamond. These new and challenging measurements rely on optimized experimental systems and the brilliance of a 3rd generation synchrotron source. For this research program, specialized cells have been designed and built, as shown in Fig. 20 (top). Although the studies are currently at a preliminary stage, the group has measured x-ray Raman spectra of water (H2O) in phases VI and VII, (Fig. 20, bottom). Using modeling techniques developed by collaborators Uwe Bergmann (Lawrence Berkeley National Laboratory) and Anders Nillson (Stanford Synchrotron Radiation Laboratory), these spectra can be used to test and validate different models of the local structure and bonding of water molecules. The work is currently being extended to higher P-T conditions, as discussed in Section 2.1. Absence of Magnetism in hcp Iron- Nickel at 11 K – The Fultz group at Caltech has led nuclear forward scattering experiments to test explanations as to why zero HMF is observed in hcp Fe, whereas ab- initio calculations show that hcp Fe should be antiferromagnetic (Fig. 21). Together with Michael Y. Hu (HPCAT), Paul Chow (HPCAT), Ronald E. Cohen (Carnegie), and Maddury Somayazulu (Carnegie), the Fultz group at Caltech has completed work that was central to the Ph.D. thesis of CDAC student Alexander Papandrew. Synchrotron Mössbauer spectroscopy (SMS) was performed on an hcp-phase alloy of composition Fe92Ni8 compressed to 21 GPa in a DAC and cooled to 11 K. The SMS spectrum Figure 20. Top, X-ray Raman cell and schematic. showed no hyperfine magnetic field. Density Left, image of cell, with large aperture for collecting functional theoretical calculations predict inelastically scattered photons. Right: schematic antiferromagnetism in both hcp Fe and hcp diagram of x-ray Raman system. Bottom: x-ray Fe-Ni. For hcp Fe, these calculations predict Raman spectra of H2O in two of its room no hyperfine magnetic field, consistent with temperature, high pressure phases. previous experimental observations. For hcp

27 Fe-Ni, however, substantial hyperfine magnetic fields are calculated, but these were not observed in the present work. There are two possibilities that can explain this negative result. First, small but significant errors in the generalized gradient approximation density functional may lead to an erroneous prediction of magnetic order, or of erroneous hyperfine magnetic fields in antiferromagnetic hcp Fe-Ni. Alternately, the presence of quantum fluctuations with periods much shorter than the lifetime of the nuclear excited state would prohibit the detection of moments by the SMS technique. A manuscript describing this work is being published in Physical Review Letters15.

Figure 21. Left: Michael Hu (HPCAT), Rebecca Stevens (Caltech), and Alexander Papandrew (Caltech) working at HPCAT. Right: SMS spectra from Fe92Ni8 at various temperatures and pressures. The numerical scale applies only to the topmost curve, and is provided as a reference. Solid lines are theoretical fits to the data. At 0 GPa and 296 K, the sample is bcc; at 21 GPa it is hcp15.

Rare Earth Metals – Another example of CDAC support of other groups is University of California – Davis graduate student Brian Maddox’s collaboration with a group from LLNL and HPCAT. They reported resonant inelastic x-ray scattering (RIXS) and x-ray emission spectroscopy (XES) results on Gd metal to 113 GPa which suggest Kondo-like aspects in the delocalization of 4f electrons. In RIXS, they measured the 3d - 2pLα emission after resonant excitation through the Gd LIII edge. The XES experiment consists of measuring the nonresonant 4d - 2p Lγl emission after excitation with high-energy x rays. Analysis of the RIXS data reveals a prolonged and continuous delocalization with volume throughout the entire pressure range, so that the volume-collapse transition at 59 GPa is only part of the phenomenon. Moreover, the Lγl x-ray emission spectroscopy spectra indicate no apparent change in the bare 4f moment across the collapse, suggesting that Kondo screening is responsible for the expected Pauli-like behavior in magnetic susceptibility115. Novel Transition Metal Nitrides – Former CDAC summer undergraduate intern Andrea F. Young together with Eugene Gregoryanz (former CDAC Scientist, now at the University of Edinburgh), Chrystele Sanloup (Universitie Pierre et Marie Curie), Sandro Scandolo (Democritos National Simulation Center in Trieste), and Russell J. Hemley and Ho-kwang Mao (Carnegie) discovered and characterized two new transition metal nitrides, IrN2 and OsN2, using laser-heated diamond-anvil cell techniques. Synchrotron x-ray diffraction was used to determine the structures of novel nitrides and the equations of state for both the parent metals as well as the newly synthesized materials. These new compounds have bulk moduli comparable with those of traditional superhard materials. For IrN2, the measured bulk modulus (K0 = 428 GPa) is just below that of diamond (K0 = 440 GPa). Ab initio calculations indicate that both compounds have a metal:nitrogen stoichiometry of 1:2 and that nitrogen intercalates in the lattice of the parent metal in the form of singly bonded N-N units16.

The work extended previous work at CDAC on HfN, ZrN, NbN116, 117, and PtN2117. For NbN, Tc was found to weakly depend on pressure in the regime from 4 to 42 GPa. Band structure calculations were performed in an effort to understand this interesting behavior. X-ray diffraction data from HPCAT show that the nitrides do not exhibit any structural phase transformations up to 52 GPa. The hardness of these nitrides was measured in cooperation with Yusheng Zhao’s group at LANL. Materials with high hardness are of prime importance for wear-resistant and protective

28 coatings. This work on nitrides complements studies carried out by LLNL scientists at HPCAT, described below. A Carnegie team led by Xiao-Jia Chen performed pressure effects on the superconducting transition temperature Tc and the electronic stiffness of niobium nitride118. Tc was found to increase initially with pressure and then saturate up to 42 GPa (Fig. 22). Combining phonon and structural information on the samples obtained from the same single crystal, a nonmonotonic pressure dependence of the electronic stiffness was derived, which rises moderately at low pressure while dropping slightly at high pressure. The theory of Gaspari and Gyorffy119 was found to reproduce the observed low-pressure results qualitatively but fails to predict the high-pressure data. The observed pressure effect on Tc is attributed to the pressure-induced interplay of the electronic stiffness and phonon frequencies.

Figure 22. Left: Dependence of the superconducting transition temperature Tc with pressure in a niobium nitride single crystal. The error bars give the transition onset uncertainty. The solid curve is a fit to the experimental data. Right: Pressure dependence of the normalized electronic stiffness in niobium nitride up to 30 GPa.

Electronic Spin Transition of in (Mg,Fe)O – Pressure-induced electronic spin-pairing transitions of iron in (Mg,Fe)O (magnesiowüstite) have been examined theoretically for half a century. Since magnesiowüstite is considered to constitute a considerable volume fraction of the lower mantle (~20%) and is probably iron-rich compared with silicate perovskite, an understanding of the electronic spin-pairing transition of (Mg,Fe)O is crucial to modeling deep-Earth geodynamics and geochemistry; however, experimental difficulties have hampered the observation of the electronic spin transition in mantle minerals under high pressures for decades. Recent developments in the X-ray Emission Spectroscopy (XES) and Nuclear Forward Scattering (NFS) at 16-IDD of the HPCAT, Advanced Photon Source (APS) are ideally suited to understand the spin states of iron in magnesiowüstite in the lower mantle pressures. Jung-Fu Lin (LLNL) and colleagues have recently observed at HPCAT an electronic transition of iron in magnesiowüstite with synchrotron Mössbauer and x-ray emission spectroscopies under high pressures120, 121. Synchrotron Mössbauer studies show that the quadrupole splitting disappears and the isomer shift drops significantly across the spin- paring transition of iron in (Mg0.75,Fe0.25)O between 52 and 70 GPa121, whereas the presence of the ’ satellite peak (Kβ ) in the x-ray emission spectra below 55 GPa is characteristic of the magnetic state of iron and the absence of the satellite peak above 67 GPa indicates the collapse of the magnetization (Fig. 23)120. Based upon in situ x-ray emission spectroscopy and x-ray diffraction to pressures of the lowermost mantle, this group found that an observed high-spin to low-spin transition of iron in magnesiowüstite results in an abnormal compressional behavior between the high-spin and the low- spin states120. The temperature effect is important for addressing the spin transition and its effects in the lower mantle, as the Earth’s lower mantle. Although experimental studies on the spin transition are mostly limited to high pressure and room temperature due to the technical difficulties, recent theoretical predictions show that the spin transition of ferrous iron in magnesiowüstite would occur

29 continuously over an extended pressure range (a spin crossover) under the P-T conditions of the lower mantle, since the changes in other physical properties of magnesiowüstite are continuous across the spin crossover. Future developments in the high P-T XES and NFS techniques at HPCAT will help better understanding of the spin transitions in these materials.

Figure 23. Left: representative synchrotron Mössbauer spectra of (a) (Mg0.75,Fe0.25)O and (b) (Mg0.75,Fe0.25)O with stainless steel (SS) as a function of pressure at room temperature (2). Black line: modeled spectrum. Right: x-ray emission spectra of (Mg0.75,Fe0.25)O under high pressures and 300 K116. Insert, the integrated area intensity of the satellite peak as a function of pressure. The intensity of the satellite peak decreases significantly across the spin transition at ~55 GPa.

IR Detector Testing for Dynamic Compression Measurements – One of the many important goals of the CDAC scientific program is to work toward merging the gap between the static and dynamic compression communities. A key aspect of this work was explored during Year 3 of CDAC as Dan Dolan from Sandia and collaborators R. Hacking and K. Moy from Bechtel Nevada tested several infrared radiation detectors at the CDAC-supported U2A beamline at NSLS to establish the feasibility of real-time infrared measurements during dynamic compression events. Technical challenges include demonstrating that the synchrotron produces sufficient light during the time duration of a dynamic compression experiment, typically ~1000 ns. Also, detectors fast enough to follow the pulsed synchrotron output are necessary. In this experiment, light from the visible- ultraviolet ring was passed through a FTIR spectrometer, and then focused onto the detectors after suitable beam conditioning. The detector output from a InGaAs photodiode is shown in Fig. 24. The well-resolved pulses suggest that real-time infrared reflectance measurements of dynamic shock compression events are feasible on the U2A beamline. Signals from HgCdTe and HgCdZnTe detectors suffered from high background, but with operation in the single pulse mode, measurements are possible.

30 Figure 24. Top left: signal output measured with a short wavelength cutoff filter (l > 850 nm transmitted). The detector yields well-resolved pulses (3-4 ns width) separated by 18 ns, when the VUV ring is operating in standard mode (570 mA beam current). Top right: Conceptual view of the impact experiment. Bottom: The design of the gas gun to be used at the NSLS U2A beamline

Superconductivity at High Pressure – Stanford University student Tanja Cuk, a student of Zhi-Xun Shen, working at CDAC facilities with Viktor Struzhkin at Carnegie investigated the high pressure behavior of Bi-based high-Tc superconductors, including pressure- induced insulator-metal transitions in AF Bi materials on studies of new classes of superconducting compounds. These high-Tc superconductors, oxides, nitrides, hydrogen compounds, borides, and carbides are potentially important for fundamental science and for application as high-temperature/high-critical parameter superconductors. For example, Struzhkin’s group also completed a study of possible superconductivity in Na under pressure. The experiments performed thus far (to 100 GPa) do not show signs of superconductivity from Na down to 5 K, work done with a high school intern, Jacob Cohen (Yeshiva of Greater Washington). Carnegie colleagues Ronald Cohen and Zhigang Wu are performing theoretical calculations (results shown in Fig. 25) on superconductivity in sodium. Raman studies were also carried out for Os (osmium) to 60 GPa ad 10-300 K to understand non-adiabatic contributions to electron-phonon coupling in collaboration with colleagues Yuri Ponosov and Alexander Goncharov. 122

31 Isotope Effect in High-Temperature Superconductors – The isotope effect is an important experimental probe in Figure 25. Calculated revealing the underlying Tc(P) in sodium122. Sodium has much lower pairing mechanism of Tc than lithium in the superconductivity. Early fcc phase, although it measurements of the isotope has the same predicted effect on the superconducting trend to increase transition temperature Tc dramatically with provided key experimental increasing pressure. evidence for the phonon- Above 120 GPa there is mediated pairing and a theoretically predicted phase transition in supported strongly the sodium. Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity in conventional materials. When high-temperature superconductivity was discovered in copper oxides, the oxygen isotope exponents, defined by α=-dlnTc/dlnM with M being the isotopic mass, were promptly measured. Experiments have revealed a much richer and more complex situation. The Carnegie group, led by Viktor Struzhkin and Xiao-Jia Chen, has now developed a phonon-mediated d-wave BCS-like model in order to explain the elaborate oxygen isotope effect19. The model accounts for the magnitude of the isotope exponent as functions of the doping level as well as the variation between different cuprate superconductors. The doping dependence of α in YBa2Cu3O7-δ resembles that of dlnTc/dP, signaling a nice correlation between the isotope and pressure effects, as shown in Fig. 26. Based on the measurements of both Tc and Raman shift of the B1g phonon mode, it was also predicted that the pressure dependence of α for the optimally doped YBa2Cu3O7-δ would be similar to that of the pressure coefficient of Tc. A unified picture for the isotope effect in cuprates is then given at ambient condition and under pressure, and supported with good agreement between theory and experiments.

Figure 26. Left: Oxygen isotope exponent α vs the superconducting transition temperature Tc in YBa2Cu3O7-δ. Theory: solid line (lower and upper curves for the underdoped and overdoped sides, respectively); experiment: open diamond, solid circle, solid squares, and open up triangles are the experimental data points taken from different groups. A maximum in α around Tc ~50 K is believed to be associated with the chain oxygen ordering. Right: Pressure dependence of both the oxygen isotope exponent α and pressure coefficient of Tc, dlnTc/dP, in the optimally doped YBa2Cu3O7-δ19.

32 The Carnegie group has also reported measurements of the oxygen isotope effect in other cuprates. Optimally doped single crystals of Bi2Sr2Can-1CunO2n+4+δ (n=1,2,3) have an isotope exponent that decreases with increasing the number of CuO2 layers in a manner inversely correlating with Tc in this homologous family123. This behavior contrasts with the general belief that the isotope effect can be negligible for the optimally doped cuprates. These results highlight the important role played by phonons and interlayer coupling in high-temperature superconductivity. The mercury-based cuprate superconductor HgBa2Can-1CunO2n+2+δ has a higher Tc both at ambient conditions and under pressure than any member of this homologous series, and the Tc strongly depends on the number of CuO2 layers per unit cell. The Carnegie group used a phonon-mediated d- wave BCS-like model to investigate the pressure effects19. Fig. 27 shows the calculated Tc as a function of pressure up to 50 GPa for the optimally doped HgBa2Can-1CunO2n+2+δ (n=1,2,3), respectively. Pressure is increased, Tc increases initially until passing a saturation at critical pressure, and at higher pressures Tc slightly decreases. The theoretical results are in very good agreement with those experimentally obtained early at Carnegie in collaboration with University of Houston group led by Paul Chu. This is the first application of the phonon-mediated d-wave BCS model to the pressure effect in cuprate superconductors. The significant Tc increase under pressure points to the possibility of enhancing Tc at ambient condition in compressed structures obtained through the preparation of epitaxial films deposited on substrates having smaller lattice parameters than those of the optimally doped Hg-based compounds.124

Figure 27. Pressure dependence of the superconducting transition temperature Tc in the optimally doped HgBa2Can- 1CunO2n+2+δ (n=1,2,3). Symbols represent experimental data and curves are the theoretical results124.

Insulator Metal Transitions – The metal-insulator transition in the Bi-based high-Tc parent compound was also studied by Viktor Struzhkin (Carnegie) and his collaborators. Phonon and magnon scattering suggest a metal-insulator transition around 25 GPa, whereas resistivity studies indicate an onset of a sluggish insulator to metal transition below 2-5 GPa. Since standard resistivity measurements in a DAC are hampered by huge contact resistance, the focused ion beam facility at Stanford has been used to prepare good contacts to their samples. The lower pressure range is being tested by graduate student Tanja Cuk (Stanford). Also underway are x-ray, Raman, and IR studies of the simple hydrides (silane – SiH4) and germane (GeH4), in a systematic search for possible insulator-metal transitions and novel syperconductivity125. Preliminary results obtained by a Carnegie team lead by Xiao-Jia Chen indicate metallization above 30 GPa on the basis of synchrotron IR measurements at U2A (Fig. 28). In addition, the crystal structure was refined by Olga Degtyareva (former CDAC research scientist, now at the University of Edinburgh), based on powder x-ray diffraction data collected at CDAC. Measurements of transport properties are in progress. Resistivity studies in Bi57FeO3 across the spin-crossover transition have shown that samples become nearly metallic above 55 GPa. A theoretical description of the transition would imply both magnetic collapse and Mott-type behavior at comparable pressures. It appears that this transition may be instrumental in providing strong coupling in this material between magnetic and

33 electric polarization through the elastic lattice interactions. Further experiments are underway to test this hypothesis.

Figure 28. Transmission photographs of silane SiH4 in a DAC under pressure. Grains of ruby are used for pressure determination. G and S represent the gasket and sample, respectively. Images are taken at 20.1 GPa (transmitted light and 31.6 GPa (reflected light), showing the dramatic changes in optical properties.

It has been suggested that the maximum magnitude of colossal magnetoresistance occurs in mixed-valent manganites with a tolerance factor t=0.96. However, at t~0.96 most manganites have relatively low values of the metal-insulator transition temperature at ~60–150 K. The Carnegie group recently found that a 50 Å La0.9Sr 0.1MnO3 thin film with t=0.96 grown on a <100> SrTiO3 substrate has a metal-insulator transition above room temperature, which represents a doubling of the transition temperature compared with its value in the bulk material. It was shown that this spectacular increase is a result of the epitaxially compressive strain-induced reduction of the Jahn- Teller distortion126. X-ray emission spectra of compressed Ge below the Ge K edge were measured at Sector 16 the Carnegie, NSLS, and HPCAT teams. The spectra show that the width of the valence band does not show any pressure dependence in the semiconducting diamond-type structure of Ge below 10 GPa. On the other hand, in the metallic β-Sn phase above 10 GPa, the valence band width increases under compression. Density functional calculations show increasing valence band width under compression both in the semiconducting phase (contrary to experiment) and in the metallic β-Sn phase of Ge (in agreement with observed pressure-induced broadening). The pressure-independent valence band width in the semiconducting phase of Ge appears to require theoretical advances beyond standard DFT or GW approximations127. Multiferroic Materials – Synchrotron Mössbauer and x-ray emission measurements, combined with x-ray diffraction, have also been completed on a variety of other potentially useful iron-containing materials, including GdFe3(BO3)4, yttrium iron garnet (Y3Fe5O12) and Bi57FeO3. Measurements on GdFe3(BO3)4 showed that the spin-crossover in the paramagnetic state could be clearly observed and that this transition has a profound influence on the other properties of the material, such as the optical gap and the anomaly in the P-V relation. In particular, the quadrupole splitting at the transition is a sensitive indicator of the low-spin state. In Y3Fe5O12 varying the pressure through the electronic transition to above 55 GPa, optical measurements of the band gap indicate an irreversible electronic transition. Interestingly, the recovered material is amorphous128. Further studies by NFS and XES techniques are required to understand the magnetic properties at the transition. Resistivity studies in Bi57FeO3 across the spin crossover transition in pressure were complemented by synchrotron Mössbauer measurements of the effect of temperature on the transition. The results are compatible with a simple energy-activation model for the two-phase mixture (low-spin and high-spin phases) at the transition.

Structural Trends in Heavy Rare Earth Metals – Pressure-induced structural phase transformations in heavy rare earth holmium have been studied by Yogesh Vohra’s group at Alabama–Birmingham via energy dispersive x-ray diffraction to 62 GPa at ambient temperature. The complete sequence of hcp->Sm-type->dhcp->fcc->dfcc (hR24) is observed for the first time with transitions at 10, 19, 54, and 58 GPa, respectively. The fcc phase is not observed as a pure phase in holmium under pressure. Figure 29 shows the structural sequence observed in energy dispersive x- ray diffraction studies on holmium. As with many other rare earths, the regions of stability of the several phases are observed to overlap, and significant hysteresis is observed. The measured volume

34 compression for holmium is V/V0 = 0.526 at 62 GPa. The heavy rare earth metal terbium was studied at HPCAT at 16-ID-B beamline using angle dispersive x-ray diffraction to pressures up to 160 GPa. These angle dispersive data are of extremely high quality and are currently being refined to identify various low symmetry structures that are common to rare earth metals after f-delocalization at high pressures. Reduced Radiative Figure 29. Observed Conductivity of pure phases in Ho up to (Mg,Fe)O at High 62 GPa. Reflections from Pressure – The flow of the copper pressure heat in Earth’s deep marker are indexed with interior plays an an asterisk, oxide peaks are marked 'o', and important role in the gasket peaks are denoted dynamics, structure, and 'g'. Emission lines are evolution of the planet. truncated for clarity of Heat from the very hot presentation. The fcc core can flow outward by phase is observed in convection, radiation, conjunction with the and conduction. The dhcp phase just before relative amount of heat the transition to flow from these distorted fcc, but never as a pure phase. The mechanisms is currently relevant pressure step under debate. was only 3.7 GPa, Experiments performed placing strict limits on at Carnegie in facilities the range of stability for supported by CDAC show the phase. The final that the radiative member of the rare earth component of thermal sequence, distorted fcc, conductivity in (Mg,Fe)O is fit to a 24 atom unit is reduced upon reaching cell in space group 166, denoted hR24. the low-spin state. The team consisting of Alexander Goncharov, Viktor Struzhkin, and Steven Jacobsen (formerly of Carnegie, now at Northwestern University) subjected single crystals of (Mg,FeO) to pressures exceeding 60 GPa and measured optical spectra in a wide spectral range. In contrast to prevailing notions, they observed enhanced absorption of the sample in the mid- and near infrared spectral range, indicating that the sample is effectively blocking much of the light compared with low pressure conditions. The notion of reduced radiative heat transfer in low-spin phases challenges existing theories on superplume stability in the lower mantle, which appears to require high thermal conductivities in order to mitigate huge temperature gradients calculated for the case of constant thermal conductivity. This work, which was published in Science129, also gives a new insight into the interpretation of the optical spectra of this important transition metal-containing oxide129.

35 Figure 30. The Tanabe-Sugano (29) diagram for Fe2+ (d6). E is the energy, B is the interelectronic repulsion parameter, Dq is a crystal field strength parameter. The vertical line at Dq/B = 2.0 corresponds the spin-pairing transition. Only the terms relevant for spin allowed optical transitions are shown [adapted from Figgis (30)]. The crystal field is assumed to be of cubic Oh octahedral symmetry. The thick gray square and thick black diamonds correspond to the positions of the absorption bands measured in the high- and low spin phases, respectively. The energies of these bands are scaled (B 0 500 cm-1) to match the T2g-Eg transition in the high-spin phase near the spin-pairing transition.

2.6 High P-T Chemistry Work in the area of high pressure-high temperature chemistry spans a wide range of endeavor, from investigating novel phase transformations to the high-pressure, high temperature synthesis of new materials, and developing advanced analytical capabilities for evaluating chemical reactions in the bulk and at interfaces, all at extreme conditions. Nitrides of Platinum and Iridium – Synthesis of superhard materials under P-T conditions is one of the fundamental problems in materials science. Noble metals do not easily form compounds with other elements, but this can be changed under pressure. Alexander Goncharov (Carnegie) and collaborators at LLNL found that platinum and iridium nitrides synthesized under conditions of 50 GPa and Figure 31. 2500 K contain pairs of single-bonded Diagram of the nitrogen atoms. Contrary to initial proposed pyrite assumptions, the stoichiometry of the structure of PtN2. compounds is MeN2 (Me=Pt,Ir) and they Gray and blue form pyrite–like structures, as determined spheres represent from x-ray diffraction, Raman spectroscopy, platinum and nitrogen, x-ray photoemission spectroscopy and first respectively17. principles theoretical calculations. The materials possess an extremely high bulk modulus (350-400 GPa), are recoverable to ambient conditions, and appear to have high hardness17 (Fig. 31). The work builds on previous studies carried out in CDAC by Eugene Gregoryanz (currently at the University of Edinburgh) and colleagues at Carnegie and HPCAT117. This research is also complemented by x- ray diffraction and computational studies, described above16. Morphology Tuned Wurtzite-Type ZnS Nanobelts – LANL’s Zhongwu Wang and colleagues reported new insights into the behavior of wurtzite-type ZnS with respect to structural stability, phase transformation and fracture. Wurtzite-type ZnS nanobelts have a metal- dominated130 surface morphology, which has the lowest surface energy (Fig. 32). Such a particular low-energy surface structure greatly expands the structural stability of wurtzite to 6.8 GPa from an unstable phase at ambient conditions, and further results in an in-situ fracture upon the explosive transformation from wurtzite to sphalerite. The group combined in-situ synchrotron x-ray diffraction

36 and TEM characterization, and observed the broken particle size to be ~10 nm. This study provides a better understanding of the morphology-tuned mechanisms that differ from those existing in bulk and three-dimensional nanoparticle counterparts. The result provides information important for designing the optimum path for synthesis of the multi-functional nanoforms with enhanced optical and electronic properties for technological application. There has been some evidence for the role of nanoparticles in earthquakes mechanisms as well as the useful symbiosis between the strong mechanical properties of nano-building blocks within a mixture of brittle nanobelts and soft protein in several kinds of biocomposites, such as bone and nacre. The observed mechanisms could enable an understanding of the microscopic mechanisms at work in these materials, with the goal of synthesizing functional nanocomposites with excellent mechanical properties20. Hydrocarbon Synthesis at High Pressure – A Carnegie- Figure 32. ZnS LLNL project supported nanobelts. The by CDAC in Year 1 showed three characteristic that methane can be surfaces abiogenically produced, at of wurtzite-type the pressures and nanobelts temperatures of Earth's and the mantle, from carbonate corresponding minerals 131. A Bassett atomic arrangements. hydrothermal diamond Inset: Scanning anvil cell (HDAC) coupled electron microscope with a temperature image of wurtzite- controller designed and ZnS nanobelts. constructed at Geophysical Laboratory, and provided by CDAC to the group of Henry Scott at Indiana University – South Bend, is being used for ongoing hydrocarbon synthesis experiments. This apparatus can be used for in situ measurements of samples between ambient pressure and 10 GPa (~300 km in depth) and up to 800°C. The current experiments are expanding the P-T-X range to determine if additional hydrocarbons (i.e., heavier than methane) can indeed form at conditions relevant to Earth’s mantle. In addition to Raman spectroscopy and x-ray diffraction, the synchrotron infrared spectroscopy at beamline U2A of the National Synchrotron Light Source is now being used as an analytical technique. New techniques will investigate the role of fO2 by buffering the DAC measurements. Pressure-Induced Transformations in Complex Alkali Hydrides – Complex alkali metal based hydrides such as LiAlH4, LiNH2, and others are particularly attractive due to their high theoretical H2 content (e.g. LiAlH4 has 10.5 wt% H2) for on-board hydrogen storage in vehicular applications. However, the parameters of hydrogen desorption/adsorption (decomposition temperature, pressure, kinetics, reversibility, etc.) of these complex hydrides have to be improved before they find widespread practical use. It is now well established that ball milling these complex hydrides can lead to a lowering of the hydrogen desorption temperature and enhanced kinetics (in the presence of catalysts). At this time, the underlying mechanisms which improve the dehydriding properties due to ball milling are still not clear. In mechano-chemical milling, the hydride materials crushed between the hardened steel balls may experience dynamic pressures up to 6 GPa. Therefore, in addition to particle size reduction, pressure-induced transformations may also occur in the hydrides. In addition, theoretical predictions have shown the possibility of significant densification (~20% decrease in molar volume) in the predicted high pressure phase. Recently, the group at University of Nevada-Reno, consisting of Dhanesh Chandra and Raja Chellappa collaborated with Carnegie scientists Steve Gramsch, Russell Hemley, Jung-Fu Lin and Yang Song to investigate the effects of pressure on LiAlH4 by in-situ Raman spectroscopy132. If such dense high

37 pressure phases can be quenched to lower pressures, this may lead to a class of materials that are both gravimetrically as well as volumetrically efficient for hydrogen storage.

The pressure-induced effects on the Al-H bonding in LiAlH4 are in contrast to the temperature effects reported by earlier workers in a Raman study of NaAlH4. The Al-H stretching modes even in the melt indicate a strong Al-H bond and thus suggest that improvements in hydrogen desorption due to catalyst addition can be explained in terms of a weakening of this bond. It was suggested in this group’s previous study that the inclusion of a high pressure process (such as ball milling) can help in such bond weakening. Now in Year 4 of the program, the group at Nevada- Reno is a CDAC academic partner, and this work will continue with a study of the high pressure behavior of various complex hydrides such as LiNH2, LiBH4, and others to systematically investigate the effect of pressure on the bonding characteristics and phase transformations in these compounds. Interface Dynamics at High Pressure – At Illinois, Dana Dlott’s research group is developing an ultrafast nonlinear vibrational spectroscopic technique termed broadband multiplex vibrational sum-frequency generation spectroscopy (SFG) to understand the dynamics of interfaces subjected to high dynamic pressures produced using laser-generated shock waves, and high static pressures produced in IR-transmitting anvil apparatus. In the second-generation SFG spectrometer, a femtosecond broad band infrared (IR) pulse and a narrow band picosecond visible pulse are combined at the sample surface or at an interface to give a spectrum that selectively probes molecular vibrations at interfaces. The group has now studied self-assembled monolayers (SAMs), energetic materials and fuel-cell electrodes. Molecular monolayers have been a continuing area of study, and now the group is moving toward studies of the surfaces and interfaces of energetic materials, on fuel cell electrodes, and is developing a diamond anvil apparatus that is optimized for nonlinear coherent spectroscopies. At Illinois, Hackjin Kim has carried out studies of energetic material surfaces and interfaces with a preliminary study on PBX9501, which is a composite consisting of HMX crystals and estane binder (Fig. 33). This work has been extended by postdoctoral associate Eric Surber and graduate student Aaron Lozano. In previous work, it was noted that HMX surfaces gave spectra with a good degree of variability, leading to the discovery that all HMX crystals studied, which are in the (insensitive) β-HMX form, have tiny bits of (sensitive) δ-HMX scattered over their surfaces. The δ-HMX had not been observed by any previous techniques, because methods such as electron microscopy that can see the tiny crystals cannot distinguish their crystal form and methods such as x-ray diffraction have not been able to see the tiny crystals. As a result of this work on the HMX and now RDX surfaces, it now Figure 33. Schematic of the interface between the face appears that there is a tremendous variability of an HMX crystal and an estane binder. SFG spectra of surface structures depending on how and see only the one-half of the HMX molecule at the crystal where the crystals were manufactured. surface plus the molecular groups at the estane surface. The group has also been developing the capability to study small molecules on active electrodes relevant to fuel cells, in collaboration with analytical chemist Andrzej Wieckowski. These are nanotextured electrodes under a thin layer of aqueous electrolyte. The immediate goal here is to understand the surface science of CO on Pt-based electrodes. CO is a poison in electrochemistry and it is a product that results from the decomposition of many useful fuels such as methanol and formic acid. Ultimately, the long-term objective will be to extend this expertise to study electroadsorbed CO with static and dynamic shock compression. The motivation for the static experiments is a better fundamental understanding of electrochemistry, since there are

38 no high-pressure spectroscopy experiments known at this point. The motivation for the shock compression experiments stems from earlier measurements of SAMs. The SAMs were very interesting, but the long-chain molecules have a complicated response. CO should have a much simpler response that can be better understood, and CO produces a giant SFG signal. This work is leading up to using shock compression as the ultimate probe of shock front structure. Nitrogen at High Pressure – A team consisting of Eugene Gregoryanz (University of Edinburgh), Alexander Goncharov, Maddury Somayazulu, Razvan Caracas, Russell Hemley, Ho-kwang Mao (Carnegie), and Chrystele Sanloup (Universitie Pierre et Marie Curie), continued study of nitrogen under extreme conditions. By combining x-ray synchrotron diffraction and different heating techniques the group has characterized phase transformations and structures of nitrogen compressed up to 170 GPa and heated above 2500 K. The x-ray diffraction data show that the familiar molecular phase ε-N2 undergoes two successive structural changes to the complex molecular phase ζ (at 62 GPa) and the newly discovered κ (at 110 GPa). The latter becomes semiconducting and amorphous upon further compression, and if subjected to very high temperatures (>2000 K), the material transforms to the nonmolecular cubic gauche phase, at pressures above 135 GPa. Group 14 Hydrides at High Pressure – Among molecular crystals, solid hydrogen carries a particular status due to the quantum nature of the H2 molecule and its fundamental interest. Metallic hydrogen has been predicted to be a superconductor with high transition temperatures in monatomic structures due to correlated fluctuations between electrons and holes in the band-overlap state. As discussed above, dense solid hydrogen has so far defied all attempts at metallization. Recently, Neil Ashcroft125 suggested that the dense group IVa hydrides should undergo a transition to a metallic and superconducting state at pressures considerably lower than may be necessary for hydrogen since it has already undergone a chemical precompression. High-pressure studies are therefore an emerging challenge in order to throw important insight on the process of metallization and high-temperature superconductivity in such a hydrogen-rich material. The Carnegie group, led by Xiao-Jia Chen, has performed various measurements including x-ray diffraction and Raman and infrared spectroscopy, on compressed silane SiH4 up to 67 GPa. The pressure-induced insulator- metal transition has been found near 30 GPa, as described in detail in Section 2.5. X-ray Induced Synthesis of 8H Diamond – Carbon is one of the most abundant interstellar materials, while x-ray radiation pervades the universe. A group of LANL scientists including Zhongwu Wang, Yusheng Zhao, Qing Xue, and Ren-Guan Duan, along with Robert T. Downs from the University of Arizona, and Razvan Caracas, Chang-Sheng Zha, and Russell J. Hemley from Carnegie have shown that exposure of single crystal graphite to intense synchrotron x-ray radiation results in new polymorphic phase of carbon22. Characterization by Raman spectroscopy, electron and x-ray diffraction demonstrates that the 8H diamond based on sp3- bonding readily forms in these experiments. 8H diamond has a hexagonal unit cell [P63/mmc (#194)] with 16 carbon atoms in the unit cell and can be described as 75% cubic diamond (3C) and 25% lonsdaleite (2H), as illustrated in Fig. 34. The appreciable stability of 8H diamond is confirmed by first-principles calculations. A higher measured density relative to cubic diamond and lonsdaleite is found, and is ascribed to compressive stresses at nanoparticle surfaces. The formation of 8H diamond by x-ray irradiation has implications for the formation of planets and interstellar dust, and adds a new dimension to the polymorphism of carbon22. First-principles theoretical results show that the formation of the 8H phase should be favored at high pressures (Fig. 35).

39 Figure 34. Crystallographic configurations of one unit cell of 8H diamond. Left: difference between cubic diamond (3C) with the sphalerite structure and lonsdaleite (2H) with the wurtzite structure; middle: one unit cell of 8H diamond that includes 75% 3C diamond and 25% 2H diamond (marked by the dotted lines); right: atomic arrangement of (001) and (010) facets of 8H diamond22.

Figure 35. First-principles calculations of 8H compared with 3C and 2H diamond. Variation of the total energy with volume for the three polymorphs 2H, 8H and 3C computed in the local density approximation of density functional theory. The volume is in bohr3 (1bohr = 0.529177 Å) and the energy in hartrees (1Ha = 27.2116 eV). The inset shows cross-sections through the valence electron density. The charge distribution in 8H combines features from both the 2H and 3C polymorphs22.

3. EDUCATION, TRAINING, AND OUTREACH 3.1 CDAC Graduate Students and Post-doctoral Associates The education, training and outreach mission of CDAC continues to focus on the support of graduate student preparation in the areas of high pressure research important to stockpile stewardship science. In Year 3 of the CDAC initiative, our ten academic partners supported a total of 19 graduate students and three postdoctoral associates. Princeton: Claire Runge (MA, 2006) Zhu Mao Caltech: Alex Papandrew (Ph.D., 2006) Matt Lucas Joanna L. Dodd Justin Purewall Chicago: Chris Seagle Berkeley: Jenny Pehl (Ph.D., 2006) Lowell Miyagi Alabama: Nicholas C. Cunningham Joel D. Griffith (M.S., 2006; continuing study for Ph.D.) Nenad Velisavljevic (Ph.D., 2006)

40 Illinois: Wentao Huang (Postdoctoral) Aaron Lozano Eric Surber (Postdoctoral) Arizona State: Erin Oelker Janellle Jenkins New Mexico: Stefanie Japel (Postdoctoral) Texas Tech Resul Aksoy Emre Selvi FL International: Srinivas Kulkarni Nishad Phatak

Figure 36. Caltech graduate student Matt Lucas at work on the x- ray spectroscopy beamline 16-I-D at HPCAT.

In addition, three graduate students supported by the National Labs, Kimberly Tait (LANL, University of Arizona), Zsolt Jenei (LLNL, University of Stockholm), and Amy Lazicki (LLNL, University of California, Davis), are working directly with the high-pressure groups. Postdoctoral associate Kirill Zhuravlev (Washington State University) is also working with the high pressure group at LANL. Texas Tech also supported four undergraduate students: Alysa Daniel, Michael Foss, Kelly Keply, and Stephanie Monk. This group was also assisted by Qiliang Cui, a professor from Jilin University (China). At this point, five graduate students have received their Ph.D. degrees with CDAC support. Three of them, James Patterson, (University of Illinois, 2004), Wendy Mao (University of Chicago, 2005) and Nenad Velisavljevic (University of Alabama-Birmingham, 2006), have continued working in the area of stewardship science. Patterson is now at the Institute of Shock Physics, Washington State University, headed by Yogendra Gupta, Mao is at Los Alamos National Laboratory working in the LANSCE division and Velisavjlevic is at Los Alamos National Laboratory working in the group of Neal Chesnut and Yusheng Zhao. CDAC graduate students continue their work on a wide variety of problems in experimental high pressure research relevant to stockpile stewardship science, spanning the fields of materials science, physics, chemistry and high-pressure mineral physics and geophysics. In addition, the Carnegie Institution has a well-established post-doctoral program, and a competitive predoctoral program as well as internships for college undergraduates and high school students. The close integration of computational theory within CDAC provides an environment in which graduate students in this area become intimately familiar with advanced experimental techniques and results, in addition to receiving exposure to state-of-the-art computational methods (e.g., Refs.133-135).

41 Publications and presentations involving CDAC-supported students and post-doctoral associates in Year 3 are listed below. Publications Aksoy, R., Y. Ma, E. Selvi, M. C. Chyu, A. Ertas and A. White, Equation of state measurements of molybdenum disulfide, J. Phys. Chem. Solids, 67, 1914-1917 (2006). Cunningham, N., N. Velisavljevic and Y. K. Vohra, Crystal grain growth at alpha-uranium phase transformation in praseodymium, Phys Rev B, 71, 012108 (2005). Griffith, J. D., Structural and magnetic measurements on Au4V under high pressures to 60 GPa, Masters Thesis in Physics, University of Alabama at Birmingham, (2006). Huang, W., J. E. Patterson, A. S. Lagutchev and D. D. Dlott, Shock compression spectroscopy with high time and space resolution, AIP Confer. Proc., in press. Lagutchev, A. S., J. E. Patterson, W. Huang and D. D. Dlott, Ultrafast dynamics of self-assembled monolayers under shock compression: Effects of molecular and substrate structure, J. Phys. Chem. B, 109, 5033- 5044 (2005). Lucas, M. S., A. B. Papandrew, B. Fultz and M. Y. Hu, Cluster expansions of phonon densities of states: Effects of local structure in Fe-Cr, Phys. Rev. B, in preparation. Ma, Y., E. Selvi, V. I. Levitas and J. Hashemi, Effect of shear strain on the α-ε phase transition of iron: a new approach in the rotational diamond anvil cell, J. Phys. Cond. Matt., 18, S1075-S1082 (2006). Mao, Z., F. Jiang and T. Duffy, Single-crystal elasticity of zoisite, Ca2Al3Si3O12(OH), by Brillouin scattering, Am. Mineral., in press. Matthies, S., J. Pehl, H. R. Wenk, I. Lonardelli, L. Lutterotti and S. Vogel, Quantitive texture analysis of HIPPO TOF diffraction spectra, J. Appl. Cryst., 38, 462-475 (2005). Merkel, S., A. Kubo, L. Miyagi, S. Speziale, T. S. Duffy, H. K. Mao and H. R. Wenk, Plastic deformation of MgGeO3 post-perovskite at lower mantle pressures, Science, 311, 644-646 (2006). Miyagi, L., S. Merkel, T. Yagi, N. Sata, Y. Ohishi and H. R. Wenk, Quantative Reitvelt texture analysis of CaSiO3 perovskite deformend in a diamond anvil cell, J. Phys. Cond. Matt., 18, S995-1005 (2006). Papandrew, A. B., M. S. Lucas, R. Stevens, B. Fultz, M. Y. Hu, I. Halevy, R. E. Cohen and M. Somayazulu, Absence of magnetism in hcp iron-nickel at 11 K, Phys. Rev. Lett., 97, 087202 (2006). Patterson, J. E., A. Lagutchev, W. Huang and D. D. Dlott, Ultrafast dynamics of shock compression of molecular monolayers, Phys. Rev. Lett., 94, 015501 (2005). Patterson, J. E., A. S. Lagutchev, S. A. Hambir, W. Huang, H. Yu and D. D. Dlott, Time and space resolved studies of shock compression molecular dynamics (invited), Shock Waves, in press. Pehl, J. and H. R. Wenk, Evidence for regional Dauphine twinning in quartz from the Santa Rosa mylonite zone in Southern California: A neutron diffraction study, J. Struct. Geol., 27, 1741-1749 (2005). Runge, C. E., A. Kubo, B. Kiefer, Y. Meng, V. Prakapenka, G. Shen, R. J. Cava and T. S. Duffy, Equation of state of MgGeO3 perovskite to 65 GPa: Comparison with the post-perovskite phase, Phys. Chem. Minerals, submitted. Qiu, W., P. A. Baker, N. Velisavljevic, Y. K. Vohra and S. T. Weir, Calibration of an isotopically enriched carbon- 13 layer pressure sensor to 156 GPA in a diamond anvil cell, J. Appl. Phys., 99, 046906 (2006). Seagle, C. T., A. J. Campbell, D. L. Heinz, G. Shen and V. B. Prakapenka, Thermal equation of state in Fe3S and implications for sulfur in Earth's core, J. Geophys. Res. - Solid Earth, 111, B06209 (2006). Selvi, E., Y. Ma, R. Aksoy, A. Ertas, A. White and S. Jagdev-Singh, High pressure x-ray diffraction study of tungsten disulfide, J. Phys. Chem. Solids, 67, 2183-2186 (2006). Speziale, S., L. Miyagi and H. R. Wenk, Strain distribution in a diamond anvil cell: Deformation of copper, J. Phys. Cond. Matt., 18, S1007-1020 (2005). Wenk, H. R., I. Lonardelli, S. Merkel, L. Miyagi, J. Pehl, S. Speziale and C. Tommaseo, Deformation textures produced in diamond anvil experiments, analyzed in radial diffraction geometry, J. Phys. Cond. Matt., 18, S933-947 (2006). Velisavljevic, N., Y. K. Vohra and S. T. Weir, Simultaneous electrical and x-ray diffraction studies on neodymium metal to 152 GPa, High Press. Res., 25, 137-144 (2005). Presentations Cunningham, N. C., W. Qiu, K. M. Hope and Y. K. Vohra, Structural trends in heavy rare earth metals at high pressure - possible f-delocalization mechanisms, Gordon Conference on Research at High Pressure (Biddeford, ME, June 25-30, 2006). Duffy, T. S. and Z. Mao, Elasticity of the olivine (Mg,Fe)2SiO4 polymorphs: Current understanding and implications for mantle composition, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006).

42 Mao, Z., F. Jiang and T. S. Duffy, Single-crystal elasticity of zoistite Ca2Al3Si3O12(OH) by Brillouin scattering, COMPRES Annual Meeting (Mohonk, NY, June, 2005). Mao, Z., F. Jiang and T. S. Duffy, Single-crystal elasticity of zoisite Ca2Al3O12(OH) by Brillouin scattering, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Merkel, S., A. Kubo, S. Speziale, L. Miyagi, H. R. Wenk, T. S. Duffy and H. K. Mao, Plastic deformation of MgGeO3 post-perovskite beyond 100 GPa, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Merkel, S., L. Miyagi, S. Speziale, H. R. Wenk, A. Kubo, T. S. Duffy and H. K. Mao, Texture development in MgGeO3 postperovskite, Eos Tran. AGU Fal Meet., Suppl., submitted (2005). Miyagi, L., Berkeley CDAC collaborations in texture analysis of Earth materials at high pressures, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Runge, C., A. Kubo, B. Kiefer, T. Uchida, Y. Wang, N. Nishiyama and T. S. Duffy, New techniques for melting curve determination at high pressures: Application to silicon, COMPRES Annual Meeting (Mohonk, NY, June, 2005). Runge, C. E., A. Kubo, B. Kiefer, T. S. Duffy, V. Prakapenka, G. Shen and Y. Meng, Equation of state of MgGeO3 perovskite to 65 GPa: Comparison with the post-perovskite phase, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Velisavljevic, N., Simultaneous electrical and x-ray diffraction studies on f-electron metals at high pressures using designer diamond anvils, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005).

3.2 CDAC Collaborators As discussed above, CDAC also has established active collaborations with high-pressure groups throughout the country and around the world. These collaborations play an important role fulfilling the mission of the center, specifically by training new students and researchers in high- pressure materials science and exposing them to problems of importance to the NNSA Labs. Some other collaborations are just starting and still others that are in the preliminary planning stages, but in all cases the infrastructure made possible by CDAC has given leverage to work on a number of exciting new research directions. The current group of CDAC collaborators includes faculty and students from the following institutions: Aarhus University, Denmark Brookhaven National Laboratory A. N. Christensen G. L. Carr Abdus Salam International Center for C. C. Kao Theoretical Physics, Lisa Miller Trieste, Italy Bulgarian Academy of Sciences S. Scandolo I. K. Bonev Argonne National Laboratory I. Mitov C. J. Benmore Daniela Paneva J. A. Cowan Rossitsa D. Vassileva W. Sturhahn California Institute of Technology J. Urquidi O. Delaire J. Zhao S. Kung Arizona State University H. Su K. Leinenweber California State University at Channel J. Yarger Islands Auburn University Tabitha Swan-Wood Y. C. Chen Case Western Reserve University J. Dong J. Van Orman T. Tzeng Carleton College Bayerisches Geoinstitut, Bayreuth Frances R. Reid Tiziana Boffa Ballaran Chinese University of Hong Kong L. S. Dubrovinsky H. Q. Lin D. J. Frost CLCR Rutherford Appleton University Anastasia P. Kantor W. G. Marshall I. Y. Kantor Cleveland State University Catherine A. McCammon J. Vitali Colby College Elizabeth Littlefield

43 Colorado College Institute of Crystallography, Moscow P. Cervantes V. V. Artemov Kristin M. Chynoweth Institute of Geochemistry, Chinese T. D. Atkinson Academy of Sciences Columbia University M. Chen D. Walker X. Xie E. Cottrell Institute for High Pressure Physics, Cornell University Troitsk W. Bassett V. Denisov Dalhousie University, Canada A. G. Gavriliuk S. A. Bonev I. S. Lyubutin Drexel University M. Yu. Popov M. W. Barsoum I. A. Trojan European Synchrotron Radiation Institute for Problems of Chemical Facility, France Physics, Chernogolovka Russia F. Berberich E. B. Gordon T. Le Bihan Institute for Solid State Physics, M. Mezouar Chernogolovka F.E.E. Gmbh, Germany Valentina F. Degtyareva D. Rytz N. I. Novokhatskaya Friedrich-Schiller-University, Germany M. K. Sakharov F. Langenhorst Institute für Mineralogie and Geoforshungzentrum, Potsdam Petrolographie, Switzerland Monika Koch-Müller W. van Westrenen H. J. Reichmann Institutio di Gioscienze e Sergio Speziale Georisorse, Italy George Washington University L. Ottolini C. Cahill Instituto Potosino de Investigación M. Frisch Cientifífica y Tecnológica, Mexico Georgia Institute of Technology T. Terrience X. Wang James Franck Institute, University of Z. L. Wang Chicago GSECARS, Advanced Photon Source Y. Feng P. J. Eng E. D. Isaacs M. Newville R. Jaramillo V. B. Prakapenka T. N. Rosenbaum M. Rivers Japanese Synchrotron Radiation S. Sutton Research Institute Ecole Normale Superieure, Lyon K. Funakoshi P. Gillet Japan Marine Science Center EPFL, Switzerland S. Nagayoshi H. Berger N. Sata L. Forro Japan National Defense Academy, G. Margaritondo Tokyo European Synchrotoron Radiation Y. Yoshimura Facility, France Jilin University, Changchun G. Aquilanti G. Zou Florida A&M University Johns Hopkins University R. Little D. R. Veblen Harvard University Karl-Franzens-Universität Graz, Austria D. R. Herschbach J. K. Dewhurst S. Rekhi S. Sharma Sarah T. Stewart-Mukhopadhyay Kent State University Indiana University – South Bend C. C. Almasan H. P. Scott Laboratoire Leon Brillouin, France Institute for Earth Sciences, Acad. I. N. Goncharenko Sinica, Taiwan E. Huang

44 Lawrence Berkeley National Northwestern University Laboratory K. Brister J. F. Banfield S. Jacobsen B. Gilbert Nuclear Research Center-Negev, LENS, Florence Israel M. Santoro I. Halevy Max Planck Institut für Chemie, Mainz Oak Ridge National Laboratory R. Boehler M. Guthrie D. A. Dzivenko C. A. Tulk M. I. Eremets Physikalisches Institut, Germany Max Planck Institut für K. J. Choi Festkörperforschung, Stuttgart G. Guenthrodt G. Gu Purdue University H. U. Habermeier P. C. Doerschuk C. T. Lin Rensselaer Polytechnic Institute K. Syassen A. Sharma C. Ulrich E. B. Watson H. Zhang Russian Academy of Sciences, Moscow Moscow State University A. G. Gavriliuk B. N. Feygelson Rutgers University Nagoya University Martha Greenblatt T. Okuchi M. V. Lobanov National Cheng-Kung University, Royal Institution, London Taiwan P. McMillan J. Kung E. Soignard National Institute for Materials Science, St. John Fisher College Japan Kristina M. Lantzky S. Nakano School of Physics & Astronomy, Tel T. Sekine Aviv, Israel National Institute of Standards and A. Milner Technology M. P. Pasternak S. Prosandeev Scripps Oceanographic Institute National Research Council, Ottawa I. Gan D. J. Klug I. Gertsman J. S. Tse J. E. Johnson National Synchrotron Radiation T. Lin Research Center, Taiwan Seoul National University, Korea Y. Q. Cai S. K. Lee C. C. Chen Soliel, France C. T. Chen R. Fourme P. Chow Steacie Institute for Molecular Science, E. P. Huang Canada H. Ishii S. Patchkovskii I. P. Jarringe Stanford University C. Kendziora G. E. Brown Naval Research Laboratory Tanja Cuk S. J. Charles SUNY-Stony Brook J. E. Butler J. Chen New Jersey Institute of Technology Jennifer Kung J. P. Carlo B. Li C. Cui L. Li Y. Qin C. Martin T. Tyson J. B. Parise Z. Zhong L. Wang New Mexico State University D. J. Weidner B. Kiefer Technological Institute for Superhard Northern Illinois University and Novel Carbon Materials, Russia D. E. Brown N. R. Serebryanaya M. R. Frank

45 Texas Christian University University of California, Berkeley R. Senter A. A. Correa Texas Tech University G. Ischina V. Levitas R. Jeanloz A. White Wren B. Montgomery J. Sandhu University of California, Davis Tokyo Institute of Technology, Japan D. M. Krol K. Hirose Brian Maddox T. Kombayashi W. E. Pickett Universidad Complutense de Madrid R. T. Scalettar J. Santamaria University of California, Los Angeles M. Varela Abby Kavner Universidad de La Laguna Anat Shahar J. Lopez-Solano Sarah Tolbert A. Mujica Michelle Weinberger A. Muños University of California, Riverside S. Radescu H. Green P. Rodriguez-Hernandez Larissa Dobrzhinetskaya Università di Roma Tre, Italy J. Zhang G. Della Ventura University of Chicago Università di Trento, Italy W. Schildkamp L. Lutterotti University of Colorado G. Mariotto C. M. Holl Università G. D’Annunzio, Italy J. R. Smyth Gianluca Iezzi H. Spetzler Universität Bonn, Germany University of Connecticut Winfried Kockelmann P. D. Mannheim N. Zotov University of Edinburgh Universitat de Valencia, Italy Olga Degtyareva D. Errandonea E. Gregoryanz C. Ferrer-Roca J. Loveday J. Pellicer-Poers R. J. Nelmes A. Segura University Firenze, Italy Universitat Politècnica de València, R. Bini Spain M. Ceppatelli F. J. Manjòn D. Chelazzi Université Catholique de Louvain, M. Santoro Belgium V. Schettino X. Gonze University of Hawaii Université Parisé G. M. Amulele P. Cartigny M. H. Manghnani University College London, UK L. Ming D. Dobson S. Sharma University of Alaska University of Illinois T. Trainor J. D. Bass University of Arizona H. Hellwig R. T. Downs W. Huang D. Krishnamoorthy A. S. Lagutchev A. Krishnamurthy Jie Li M. Origlieri University of Kaiserlautern, Germany C. T. Prewitt H. J. Jodl Kimberly Tait J. Kreutz H. Yang University of Louisville University of Arkansas G. A. Lager A. Khanna University of Manitoba, Canada University of Bristol, UK F. Hawthorne H. Darwish University of Maryland A. E. Mora A. J. Campbell J. W. Steeds B. Liang

46 University of Michigan University of Texas, Arlington Wendy Panero S. Sharma L. Stixrude University of Tokyo University of Minnesota S. Merkel S. Demouchy M. Takigawa University of Missouri, Kansas City T. Yagi B. Chen University of Toronto E. P. Gogol M. Fujihsaki M. B. Kruger University of Tsukuba J. Murowchick K. Matsuishi University of Nevada-Las Vegas University of Warsaw, Poland A. L. Cornelius W. Grochala M. Daniel University of Warwick, UK C. L. Gobin D. L. Carroll E. Kim M. L. Newton R. S. Kumar University of Western Ontario, Canada Kristina Lipinska-Kalita S. R. Shieh Patricia E. Kalita University of Wyoming J. McClure S. Sampath M. Nicol Verkin Institute, Kharkov T. Pang Y. A. Freiman Y. Shen M. A. Strzhemechny W. Stanberry S. M. Tret’yak I. Tran Vernadsky Institute, Moscow O. Tschauner Delia Tchkhetia University of New Mexico M. A. Nazarov C. Agee Virginia Polytechnic Institute University of Northern Florida R. J. Angel L. V. Gasparov B. E. Hanson D. Arenas Carla Slebodnick University of Paris VI Nancy L. Ross J. Badro J. Zhao G. Calas Waseda University, Tokyo G. Fiquet Y. Ohki Chrystele Sanloup Washington State University University of Tennessee J. E. Patterson M. Anand Woods Hole Oceanographic Institution L. A. Taylor N. Shimizu

3.3 Undergraduate Student Participation A number of university undergraduate students participating in the highly successful Carnegie Summer Intern Program have worked on projects directly related to CDAC goals during the past year. This NSF-funded program, which is run by CDAC coordinator Stephen Gramsch, seeks to identify students at smaller institutions who may not have the opportunity for front-line research during the academic year, or students without a significant research background. At Carnegie, such students are provided with an introduction to scientific research, and within the structure of CDAC, are learning about the important problems in the field of high-pressure research. During the summers of 2005-2006, the following students participated in this program. 2005: Edward Banigan, Georgetown University Equations of State of MgAl2O4 Spinel Elizabeth Littlefield, Colby College Effects of Water on the Behavior of MgSiO3 Clinoenstatite at High Pressure Lisandra Rosario, Universidad Metropolitana (Puerto Rico) Solid Solutions in the Hematite-Alumina System

47 Isaac Tamblyn, Dalhousie University (Canada) Molecular Dynamics Simulations of H2-He Mixtures Catherine Tarabrella, West Virginia University Crystal Structures of CsI and CsCl at High Pressures

Figure 37. 2005 Carnegie summer intern Elizabeth Littlefield (Colby College) at the U2A infrared beamline at the National Synchrotron Light Source. Elizabeth worked with Steve Jacobsen (now at Northwestern University).

2006: Cheng Chin, Columbia University Optical Emission Spectroscopy of Simulated Microwave Plasma Enhanced CVD Diamond Growing Process Benjamin Haugen, University of Colorado Optical Absorption Spectra of Iron-Bearing Magnesium Silicate Perovskite at Lower Mantle Pressures Seth Jacobsen, Cornell University A Genetic Algorithm for Predicting High-Pressure Phases of Water Ice Frances Reid, Carleton College High-Pressure Synchrotron Infrared Studies of OH in Silicate Perovskite Robert Thomas, University of Maryland Platinum Group Element Partitioning in the Iron-Sulfur-Ruthenium System

Figure 38. Summer interns working on CDAC projects as part of the 2006 Carnegie Summer Intern Program. Top row (l-r): Frances Reed (Carleton College), Benjamin Haugen (University of Colorado), and Seth Jacobsen (Cornell University). Bottom row (l-r): Cheng Chin (Columbia University) and Robert Thomas (University of Maryland).

48 Figure 39. Summer Interns Seth Jacobsen (Cornell University), Benjamin Haugen (University of Colorado), and Robert Thomas (University of Maryland) presenting their work at the Carnegie Institution of Washington Summer Intern Research Symposium on August 10, 2006.

Former CDAC summer undergraduate intern Andrea F. Young was the first author on two papers in 2006. The first, published in Physical Review Letters, was on the discovery of new metal nitrides. This work was done in collaboration with former CDAC Scientist Eugene Gregoryanz (currently at the University of Edinburgh), Crystele Sanloup (Universitie Pierre et Marie Curie), Sandro Scandolo (Democritos National Simulation Center in Trieste), Russell J. Hemley, and Ho-kwang Mao (Carnegie)16. The second paper was on a theoretical study of PtN2 and appeared in Physical Review B136. He carried out the latter work during a 2005 internship summer in Trieste at the Democritos National Simulation Center. He has finished studies at Columbia University will be starting graduate school in physics. 3.4 DC Area High School Outreach Every year at Carnegie, several local high school students are hosted and offered guidance in their science fair projects and in other areas of research. In 2005, two Figure 40. Former CDAC summer students from Washington, DC and one student from New intern Andrea F. Young, pictured York worked on various projects with Carnegie scientists. with Eugene Gregoryanz (former In 2006, Jacob Cohen returned to work with Viktor CDAC scientist, now at the University of Edinburgh), conducting x-ray Struzhkin to work on the quantum effects of a phase diffraction experiments at HPCAT. transition. Alexander Levedahl and CDAC lab manager/research scientist Maddury Somayazulu the preparation and characterization of a hydrogen clathrate hydrates. Andrew Kung worked with CDAC lab manager/research scientist Chang-Sheng Zha on the development of resistive heating methods for hydrogen at high pressure. Kung measured the frequency of the H2 vibron at 20 GPa, from 300 to 500 K. All three students are continuing their work at Carnegie over the course of the 2006-2007 school year. 2005 high school student Cheng Chin returned to Carnegie as a summer intern and continued his work with Chih-Shiue Yan.

49 2005: Cheng Chin, Forest Hill High School, New York (Columbia University, fall of 2005) Optimizing Parameters for CVD Diamond Synthesis Daniel Cohen, Yeshiva of Greater Washington, Washington, DC Quantum Effects on a Phase Transition Jacob Cohen, Yeshiva of Greater Washington, Washington, DC Superconductivity in Compressed Sodium; Exchange Correlation Functionals for PbTiO3 2006: Jacob Cohen, Yeshiva of Greater Washington, Washington, DC Quantum Effects on a Phase Transition Andrew Kung, Winston Churchill High School, Potomac, MD Development of Resistive Heating Methods for Hydrogen at High Pressure Alexander Levedahl, St. Anselm’s Abbey School, Washington, DC Preparation and Characterization of a Hydrogen Clathrate Hydrate

Figure 41. 2006 high school summer interns at Carnegie. Left: Jacob Cohen (Yeshiva of Greater Washington). Center: Alexander Levedahl (St. Anselm’s Abbey School). Right” Andrew Kung (Winston Churchill High School).

3.5 Synergy of 21st Century High-Pressure Science and Technology Workshop A workshop was convened to explore the synergy of 21st century high-pressure science and technology. It was held from April 29 to May 1, 2006 at the APS. The workshop jointly sponsored by CDAC, COMPRES, and HPCAT. The meeting featured an extensive array of forward-looking presentations along with ample opportunities for discussions among the 112 scientists and 20 graduate students and postdoctoral researchers in attendance. The attendees represented the fields of physics, chemistry, materials science, biology, and earth and planetary sciences, from both academic institutions and the National Labs around the country. The aims of the Workshop were to review the status of US high-pressure research and to identify future grand challenges in the following nine thrust areas: • Integrated high pressure science • Dense condensed-matter physics • Chemical bonding under compression • High-pressure materials research • High-pressure petrology and mineralogy • Deep Earth geochemistry • Mission to the Earth’s core • High pressure seismology and elasticity • Biological and organic systems under pressure

50 Fifty-nine talks were given by experts from a wide variety of disciplines within the field of high pressure research. The talks reviewed the surge of high pressure discoveries in recent years as well as the technological advances in the development of new high-pressure instrumentation and analytical probes, and raised scientific and technological issues concerning the upcoming challenges for high pressure research in the 21st century. The group discussed the great scientific potential in establishing a next- generation “synergetic consortium” that would integrate state-of-the-art high-pressure techniques, facilities, and probes, and make them readily accessible to multidisciplinary high-pressure scientists. The consortium would enable high- pressure specialists and non-specialists alike to focus on specific scientific goals which were previously hindered due to technical limitations. In the three-day workshop, presentations focused on the synergy and interdisciplinary nature of the multiple subfields of high-pressure science and technology. On the first day, an introductory session explored the chemical and physical fundamentals of matter at high densities. These presentations set the stage for an extensive group of talks that demonstrated how both static and dynamic Figure 41. 2006 high school experiments, particularly in combination with each summer interns at Carnegie. other, along with condensed-matter theory, can Left: Jacob Cohen (Yeshiva of provide a means to unravel the phenomena governing Greater Washington). Center: the behavior of matter under extreme conditions. The Al d L d hl (St second day started with an overview of recent progress in seismology and geodynamics and then identified questions to be answered and the role that high pressure mineral physics can play in sorting out some of the pressing questions in these fields. Answers to some of these problems were pursued during talks in the later sessions on high- pressure mineral sciences, in which new results, developments, and technologies were presented. The day ended with two talks outlining current work in the area of biological and organic systems under high pressure. On the third day, recent developments in the studies of Earth’s deep interior were discussed from both experimental and theoretical viewpoints. The need for a synergetic consortium was further emphasized in these presentations, for example, to lead the development of a new generation of “designer” samples and anvils, integrated studies with various probing techniques, cooperation between theory and experiment, and coordinated educational efforts among different research groups. Besides the in-depth discussions in the APS conference room, two facility tours of the APS were provided during the workshop. The participant reception to the program was overwhelmingly positive, with many compliments on the outstanding quality of the talks and discussions. The workshop will result in a publication of a series of visionary papers in the Proceedings of the National Academy of Sciences, designed to illustrate the synergetic nature of the interdisciplinary field of high pressure research. Students – Workshop students came from universities throughout the United States as well as from the National Laboratories. A detailed list of students and postdoctoral researchers and their home institutions is given below:

51 Alice Acatrinei – Los Alamos National Laboratory Resul Aksoy – Texas Tech University (CDAC graduate student) Rusty Cooper – UIUC Ji Feng – Cornell University Yejung Feng – University of Chicago Itzhak Halevy – California Institute of Technology Xinguo Hong – GSECARS Jennifer Jackson – Carnegie Institution of Washington Steven Jacobsen – Carnegie Institution of Washington Stefanie Japel – New Mexico State University (CDAC postdoctoral associate) Rafael Jaramillo – University of Chicago Svetlana Kharlamova – Advanced Photon Source Michael Lerche – Advanced Photon Source Hongbo Long – SUNY-Stony Brook Wendy Mao – Los Alamos National Laboratory (former CDAC graduate student) Chris Seagle – University of Chicago (CDAC graduate student) Emre Selvi – Texas Tech University (CDAC graduate student) Eric Surber – University of Illinois (CDAC postdoctoral associate) Yuan-Chieh Tseng – Northwestern University Kirill Zhuravlev – Los Alamos National Laboratory

Figure 43. Students and lecturers of the 2006 Workshop on Synergy of the 21st Century High- Presure Science and Technology, held at the Argonne National Laboratory

Lecturers – Lectures were given in 11 sessions throughout the workshop. The following lists are divided by session and give the lecturers, their institutions, and the titles of the lecture(s) they presented. Lecturers supported by CDAC funds (staff, partners, post-docs, etc) are designated by an asterisk (*). SESSION 1: Integrated High Pressure Science Ho-kwang Mao* (Carnegie), Synergy in high-pressure research Roald Hoffman (Cornell University), The chemical imagination at work in very tight places

52 Chi-Chang Kao (Brookhaven), Electronic structure of materials under high pressure David J. Stevenson (Caltech), Planetary high pressure physics inside and outside our solar system

Figure 44. Left to right: Roald Hoffman (Cornell University) and David Stevenson (Caltech) presenting talks in the first session.

SESSION 2: Dense Condensed-Matter Physics I Russell J. Hemley* (Carnegie), Current problems in high-pressure science Brent Fultz* (Caltech), Phonon thermodynamics in materials under extreme conditions Dana Dlott* (University of Illinois), Interfaces at high pressure Alexander Goncharov* (Carnegie), Optical spectroscopy under extreme conditions Viktor V. Struzhkin* (Carnegie), Magnetism and superconductivity at high pressures SESSION 3: Dense Condensed-Matter Physics II Yogendra Gupta (Washington State University), Understanding condensed matter at extreme conditions: how to integrate dynamic and static compression methods Yogesh Vohra* (University of Alabama – Birmingham), Grand challenges in f-electron metals research at high pressures and low temperatures using designer diamond anvils Malcolm F. Nicol (UNLV), On some not-so-sharp phase transitions Stan Tozer, (National Magnetic Laboratory), Spectroscopies to aid in the B P/T exploration of condensed matter physics Wolfgang Sturhahn (Argonne), Inelastic x-ray and nuclear resonant scattering Ji Feng (Cornell University), Metallization of structural distortion under high pressure

Figure 45. Left to right: Malcolm F. Nicol (University of Nevada – Las Vegas) and Yogendra Gupta (Washington State University) presenting talks in the third session.

SESSION 4: Chemical Bonding under Compression Raymond Jeanloz (Berkeley), Gigabar pressures and kilovolt chemistry Choong-Shik Yoo (LLNL), Electronic structure of materials under high pressure Nancy Ross (Virginia Tech), Electron density of materials at high pressure Jeffrey L. Yarger* (Arizona State University), Structural transformations in liquids and

53 glasses under extreme conditions Yusheng Zhao (LANL), Neutron's prospects on the future hydrogen economy Martin Kunz (Advanced Light Source), Experimental opportunities at the high-pressure beamline 12.2.2 of the ALS

Figure 46. Raymond Jeanloz (University of California – Berkeley) presenting a talk in the fourth session.

SESSION 5: High Pressure Seismology and Elasticity Adam M. Dziewonski (Harvard University), Seismic tomography and mineral physics: questions to be answered Donald V. Hemlberger (Caltech), Review of lower mantle seismic complexity Barbara Romanowicz (Berkeley), Towards direct seismic waveform inversion for thermal and compositional 3D structure of the mantle: what we need from mineral physics David A. Yuen (University of Minnesota), The role of high pressure mineral physics in geodynamics Donald Weidner (SUNY – Stony Brook), Measuring stress at high pressure

Figure 47. Left to right: Donald V. Helberger (Caltech) and Barbara Romanowicz (University of California – Berkeley) presenting talks in Session 5.

SESSION 6: Mission to the Earth’s Core Bruce A. Buffett (University of Chicago), Evolution and dynamics of the Earth's core: current questions and new opportunities Wendy L. Mao (LANL), Elasticity of Fe-rich silicate post-perovskite Jie Li (University of Illinois), Thermal expansion of iron-rich alloys and the light element composition of the core Dion L. Heinz* (University of Chicago), Experimental studies of core materials at core conditions Guoyin Shen* (HPCAT), Experimental studies of phase diagram of iron SESSION 7: High Pressure Mineral Sciences I Juhn G. Liou (Stanford University), Orogenic UHP garnet peridotite: a new window for mantle petrochemical processes William A. Bassett and Kenji Miebe (Cornell University), Hydrothermal DAC, the value of visual observations Ross Angel (Virginia Tech), Determining intersite cation partitioning at high pressure

54 J. Michael Brown (University of Washington), Whither mineral physics? Yingwei Fei* (Carnegie), Challenges in studying the chemistry of deep interior of the Earth Thomas S. Duffy* (Princeton University), Elastic properties of hydrous minerals and implications for seismic studies of the upper mantle SESSION 8: High Pressure Mineral Sciences II Jay Bass (University of Illinois), Some recent advances in velocity measurements at high pressures and implications for the Earth Baosheng Li (SUNY – Stony Brook), Characteristics of thermal and chemical heterogeneities in the lower mantle Hans-Rudolf Wenk* (Berkeley), Deformation experiments at ultrahigh pressure: where we are and where we should be going Robert C. Liebermann (SUNY – Stony Brook), Ultrasonic measurements of sound velocities in minerals under mantle pressure and temperature conditions in conjunction with synchrotron x-radiation Yanbing Wang (University of Chicago), High P-T structural refinement of CaSiO3 (±Al2O3) perovskite Jennifer M. Jackson* (Carnegie), Physical properties of minerals and melts under high- pressure SESSION 9: Biological and Organic Systems under Pressure Keith Brister (Northwestern University), Opportunities at ultra low high pressures Anurag Sharma (Rensselaer Polytechnic Institute), Organic synthesis and biology at high pressures SESSION 10: Deep Earth Geochemistry, Petrology and Mineralogy I Ronald E. Cohen* (Carnegie), Theory of iron at high pressure and temperature Renata M. Wentzcovitch (University of Minnesota), Dissociation of MgSiO3 in the cores of the giants and in terrestrial exoplanets John B. Parise (SUNY – Stony Brook), The way frameworks respond to pressure Anne M. Hofmeister (Washington University), High pressure thermal conductivity Joseph Smyth (University of Chicago), Effects of hydration on physical properties of mantle minerals Sang-Heon Shim (MIT), Phase transition in the Earth's mantle Abby Kavner (UCLA), Experimental high pressure mineral physics in 3-Di Steven D. Jacobsen* (Carnegie), Identifying hydration in the mantle transition zone: emerging constraints from mineral physics and seismology SESSION 11: Deep Earth Geochemistry, Petrology and Mineralogy II Harry W. Green (UC – Riverside), Shearing instabilities at high pressure, application to deep earthquakes, and progress toward experiments in-situ Shun-Ichiro Karato (Yale University), Deep mantle melting and geochemical tests of the transition-zone water-filter model Jiuha Chen (SUNY – Stony Brook), Melts density study at high pressures using x-ray absorption and diffraction enhanced imaging Larrisa Dobrzhinetskaya (UC – Riverside), A look inside of diamond-growing fluid: observations from natural samples and experiments William B. Durham (LLNL), High-pressure rheology: challenges and opportunities

55 Figure 48. William B. Durham (formerly of LLNL, now at MIT) presenting his talk during the eleventh session.

3.6 Visitors to CDAC As part of CDAC’s outreach program, Carnegie receives many visiting scientists each year. These scientists utilize the Carnegie laboratory facilities to prepare and perform experiments that would be impossible to do at their home institutions. Scientists from around the country and the world have visited Carnegie to take advantage of this program.

Visitors Affiliation Project Date Jennifer Ciezak NIST; Aberdeen Army Energetic materials September 8, 2005- Laboratory ongoing N. Nath Physics Dept., Indian Interlayer exchange coupling in September 29, 2005 Institute Of Technology, Fe/Nb multilayers Kanpur M. D. Fuller Fuller & Associates Diamond analysis October 3, 2005 Lore Kiefert American Gem Trade Association Y. Zhao Lawrence Livermore Clathrates Hydrates: Science October 14, 2005 National Laboratory and Technology Valentina Institute for Solid State High pressure crystallography October 17, 2005 – Degtyareva Physics, Chernogolovka December 20, 2005 S. N. Tkachev Hawaii Institute of Compressibility of Hydrated October 31, 2005 Geophysics and and Anhydrous Sodium Planetology Silicate-based Liquids and Glasses, as Analogues for Natural Silicate Melts, by Brillouin Scattering Spectroscopy R. Clark Morgan Crucible Diamond analysis November 3, 2005 E. Surber University of Illinois Diamond cell work November 7-14, 2005 Urbana-Champaign J. Butler Naval Research Lab. Diamond analysis November 8, 2005 J. Post Smithsonian Institution Q. Peng University of Localization of plastic shear November 17, 2005 Connecticut events in glassy materials J. Feldman Naval Research Lab. Hydrogen November 17, 2005 E. V. Tisper George Mason University Nathalie Bolfan- Laboratoire Magmas et Water in the Earth’s mantle December 12-13, Casanova Volcans 2005 D. Andrault Institut de hysique du Mineral properties at high December 13, 2005 Globe du Paris pressure and temperature Wendy L. Mao LANL Hydrogen storage and D” December 27, 2005- collaboration projects January 8, 2006

56 Michelle University of Investigating the mechanical January 4-11, 2006 Weinberger California – Los Angeles properties of self-organized nanomaterials and new ultra- incompressible superhard materials Min Ouyang University of Maryland – Nanospintronics: quantum January 5, 2006 College Park mechanics, nanomaterial synthesis and device discovery K. Delaney University of Illinois, Simulating the behavior of January 12, 2006 Urbana-Champaign hydrogen fluid at high pressure R. Clark Morgan Crucible Diamond analysis January 12, 2006 T. Autrey Pacific Northwest Mechanistic studies of February 2, 2006 National Library molecular hydrogen formation from borane ammonia complexes R. Chellappa University of Nevada – Raman work on aluminum February 8-24, 2006 Reno hydrides Tanja Cuk Stanford University Hi Tc superconductors under February 6-April 24, pressure transport properties 2006 R. Hamburg Diamond analysis February 21, 2006 R. Spirto A. Boone J. Walters K. Esler University of Illinois Talk on quantum Monte Carlo February 23, 2006 methods for simulating matter under extreme conditions J. Lucek Diamond Innovations Diamond analysis February 27, 2006 Wren Montgomery University of Talk on high-pressure prebiotic February 27, 2006 California – Berkeley chemistry Liping Huang University of Michigan Talk on demystifying the February 28, 2006 behaviors of network-forming systems under extreme conditions Yufei Meng Sun Yat-sen University Talk on defects and coloration March 7-14, 2006 mechanism of brown diamond Angele Ricolleau Institute Phys. Du Globe Talk on subduction of the March 8, 2006 oceanic crust in the Earth's lower mantle: a petrological study D. Lakshtanov University of Illinois Gas loading March 9, 2006 Urbana-Champaign M. Newton University of Warwick Diamond analysis March 10, 2006 J. Butler Naval Research Lab. R. Reiclin National Science Diamond analysis March 10, 2006 Foundation Kristina Lipinska- University of Nevada – Lab visit after APS meeting March 17, 2006 Kalita Las Vegas Patricia Kalita C. L. Gobin Wendy Mao LANL Hydrogen storage and D” April 5, 2006 collaboration projects L. Bildsten University of California Physics of white dwarfs April 17, 2006 – Santa Barbara J. Palfreman Palfreman Film Group Interview with R. J. Hemley May 4, 2006 T. Nugent Chicago Tribune Interview with R. J. Hemley May 4, 2006 D. Dlott University of Illinois Talk on vibrational May 8, 2006 Urbana-Champaign spectroscopy with high time and space resolution

57 J. Hwang Taiwan University Diamond analysis May 9-11, 2006 C. Chu T. Baofang J. Chang Y. Feng University of Chicago Pulsed laser system May 25, 2006 A. Sharma Rensselaer Polytechnic Talk on following biofuels to May 26, 2006 Institute the extreme Kimberly Tait University of Arizona Talk on hydrogen storage in May 31-June2, 2006 clathrate W. Holder Wesleyan University Tour of the Geophysical June 16, 2006 Laboratory Y. Ma Texas Tech University Laser heating July 7-24, 2006 A. C. Kollias University of California Extending accuracy of QMC August 1, 2006 – Berkeley from total energies to observables and small differences of energies I. Khodakovsky University of Dubna Library research August 14, 2006 A. Prisco GI Corporation Diamond analysis August 14, 2006 R. Gat C. Hill Diamond analysis August 15, 2006 C. Vaughn Penn State Electro- Diamond analysis August 29, 2006 V. D. Heydemann Optics Center D. Snyder M. Fanton J. Carter C. Tulk Oak Ridge National SNAP update September 12, 2006 S. Chae Laboratory J. Molaison P. Lazor University of Uppsala Gas loading ammonia September 21-22, 2006 H. P. Liermann HPCAT Helium gas loading September 26-27, 2006 A. Martinez Opticut, Inc. Diamond cutting September 29- October 2, 2006 Svetlana Argonne National Sample preparation in DAC for October 2-October 4, Kharlamov Laboratory synchrotron experiments 2006 W. Sturhahn Argonne National Talk on sound velocites October 9-October 10, Laboratory of iron-bearing Earth materials 2006 under extreme conditions

3.7 High Pressure Seminars Several times a month, CDAC holds informal seminars at Carnegie. These seminars are open to the high-pressure community and cover new and exciting topics in the world of high-pressure science and technology. Speakers come from within CDAC as well as from around the world.

Speaker Affiliation Topic Date N. Nath Physics Dept., Indian Interlayer exchange coupling in September 29, 2005 Institute Of Technology, Fe/Nb multilayers Kanpur Y. Zhao LANL Superhard materials October 14, 2005 L. Shi George Mason Superconductivity of alkali October 20, 2005 University metals under high pressure and revisions of Harrison's tight- binding theory

58 S. N. Tkachev Hawaii Institute of Compressibility of hydrated October 31, 2005 Geophysics and and anhydrous sodium silicate- Planetology based liquids and glasses, as analogues for natural silicate melts, by Brillouin scattering spectroscopy E. Surber University of Illinois Surfaces and interfaces of high November 8, 2005 Urbana -Champaign explosives probed by nonlinear spectroscopy Q. Peng University of Localization of plastic shear November 17, 2005 Connecticut events in glassy materials Sara Seager Carnegie Interiors of low-mass December 1, 2005 exoplanets M. Ouyang University of Maryland – Nanospintronics: quantum January 5, 2006 College Park mechanics, nanomaterial synthesis and device discovery Michelle UCLA Investigating the mechanical January 10, 2006 Weinberger properties of self-organized nanomaterials and new ultra- incompressible superhard materials Kris Delaney University of Illinois Simulating the behavior of January 12, 2006 Urbana -Champaign hydrogen fluid at high pressure Jennifer Jackson Carnegie Melting investigations of iron January 27, 2006 at high-pressure using synchrotron Mossbauer spectroscopy T. Autrey Pacific Northwest Mechanistic studies of February 2, 2006 National Library molecular hydrogen formation from borane ammonia complexes S. Tkachev Carnegie Brillouin spectroscopy studies February 22, 2006 of hydrated and anhydrous sodium S K. Esler University of Illinois Quantum Monte Carlo methods February 23, 2006 for simulating matter under extreme conditions P. Beck Carnegie Martian and chondritic February 24, 2006 meteorites impact record Wren Montgomery University of California High-pressure prebiotic February 27, 2006 – Berkeley chemistry Liping Huang University of Michigan Demystifying the behaviors of February 28. 2006 network-forming systems under extreme conditions Angele Ricolleau Inst. Phys du Globe Subduction of the oceanic crust March 8, 2006 in the Earth's lower mantle: a petrological study Yufei Meng Sun Yat-sen University Defects and coloration March 10, 2006 mechanism of brown diamond M. Newton University of Warwick Studies of defects in diamond March 10, 2006 C. Glass ETH, Zurich USPEX - Predicting crystal March 23, 2006 structures of new phases S. Vance University of Physical chemistry, fluid March 24, 2006 Washington dynamics, and the search for life in extraterrestrial oceans J. Xu Carnegie Moissanite anvils and anvil March 31, 2006 pressure cells used in neutron diffraction

59 G. Managadze Russian Academy of New scenario and universal April 27, 2006 Sciences mechanism for the prebiological state of evolution C. S. Zha Carnegie Highlights of high pressure May 12, 2006 experiments at CHESS H. Kanda National Institute for Characterizing defects in May 18, 2006 Materials Science natural diamond Tsukuba, Japan A. Sharma RPI Some ideas on following May 26, 2006 biofuels to the extreme Kimberly Tait University of Arizona Hydrogen storage in clathrate May 31, 2006 A. C. Kollias University of California Extending accuracy of QMC August 1, 2006 – Berkeley from total energies to observables and small differences of energies C. S. Zha Carnegie Review of current resistive August 9, 2006 heating techniques: what works, what doesn't P. Lazor University of Uppsala High pressure development in September 22, 2006 Uppsala Q. Liang University of Alabama – Applications of nanocrystalline September 29, 2006 Birmingham diamond

4. TECHNOLOGY DEVELOPMENT 4.1 High P-T Experimental Techniques Heating and Spectroscopic Methods – An important part of the CDAC mission has been the advancement of high-temperature/high pressure techniques by bringing together the technical strengths from academic and the National Labs (both NNSA and other DOE Labs). Indeed, the many advances in dynamic ultrahigh-pressure techniques such as laser driven shocks produced from intense laser sources137, 138, gas-guns139, and magnetic compression methods140 and continued refinements of DAC techniques at the NNSA Labs form a natural complement to activities within CDAC141, 142. Advances made in high-temperature methods at ultrahigh pressure are providing new links to dynamic compression experiments. The Nd-YLF double-sided laser method143, 144 has been extended to include CO2 laser heating as well as simultaneous Raman spectroscopy45, 145, and this technique has become routine in a number of laboratories, among them the groups of Choong-shik Yoo and Joe Zaug/Jonathan Crowhurst at LLNL, and the CDAC group at Carnegie. Laser heating in the DAC has been further developed by Alexander Goncharov (Carnegie) to allow in situ Raman studies to higher temperatures. Various coupler materials and configurations were tested, that allow performing several runs in simple molecular materials (H2 and N2) to approximately 1000 K and 60 GPa. Also different thermal insulations are being tested. This work is in progress. In addition, a pulsed Raman apparatus has been constructed at Carnegie17. The latter provides a substantial suppression of the thermal radiation, so experiments to higher temperatures will be feasible. A pulsed heating technique with 10 ns pulsed YAG laser is being developed. This technique allows reaching high temperatures in a short period of time, so the experiments can be performed in a time domain, reducing the risk of chemical reactivity. This development is also in progress. Data from nuclear resonant inelastic scattering measurements show that the Planck function and the temperature as measured by NRIXS are good agreement up to at least 1700 K146, indicating that spectroradiometric determination of the temperature is reliable. Meanwhile, resistively-heated DACs, which provide a temperature accuracy of ±5 K, have been extended to above 1000 K at megabar P, even for hydrogen147. The state of the art in this technique is undergoing a period of rapid change at Carnegie as well under the leadership of CDAC research scientists Maddury Somayazulu and Chang-Sheng Zha, who are leading the development of new cell designs for use in a variety of x-ray and optical spectroscopy experiments. Available sample

60 volumes continue to increase with improvements in gasketing methods now in use at a number of CDAC nodes148, 149. Rotational DAC (RDAC) studies were discussed in Section 2.1. Since the RDAC possesses the advantages a DAC – flexible, compact, and light-weight – along with the unique function of generating shear stress and strain, it may well be expected that the rotational diamond anvil to become one of the most powerful methods in the exploration of materials under pressure and shear. The technology can be extensively utilized to explore the effect of shear stress, pressure and temperature of a variety of materials. Non-linear optical methods developed at Illinois, including the recent breakthrough in the use of vibrational sum-frequency generation (SFG) to probe molecules at interfaces, are undergoing continuous development and are being applied to high-pressure problems. Now in its second generation, the technique can now be applied to investigate the structure, chemistry and aging properties of molecules at interfaces and crack propagation relevant to stockpile stewardship. Much of this work will set the stage for new advances in high-pressure materials science, including the use of free-electron lasers and combined static/laser shock methods. At Carnegie, Brillouin spectroscopy has been an important technique for measuring subtle structural effects at high pressure. During Year 3, the spectrometer was completely upgraded under the direction of Muhetaer Ahart, the most important new feature being an acoustic modulator and double shutters at the entrance to the scattering pass, which make it possible to reduce the elastically scattered (Rayleigh) light, and which now allows the use of the Rayleigh light to control the stabilization system. The control units, photon-counting system, and all the piezo-devices have been upgraded or replaced, so now the detected signal can be obtained from the control unit directly. Since the installation of these upgrades, the acquisition time for Brillouin spectra has decreased by an order of magnitude (e.g., tens of minutes to a few minutes). These improvements should bring the technique firmly into the array of capabilities available to the CDAC membership. CVD Diamond – The most important breakthroughs in the area of technology development have been in the area of epitaxial CVD diamond growth, where the Carnegie group has continued to perfect processes for the fabrication of single crystal diamond by the microwave plasma CVD process. The primary effort during the past year has been on increasing growth rates, which now are consistently 50-200 µm/hr, based on the quality of the diamond produced. Now the Carnegie group can routinely produce 10-carat, half-inch thick single-crystal diamonds of varying quality (Fig. 31). An important factor in the success of the CVD process was the close collaboration with a group from LANL early on in the CDAC program150. As grown, the material has high fracture toughness and upon high temperature/high pressure annealing (a process also developed and perfected at Carnegie) its hardness can increase dramatically, reaching values some 50% higher than conventional diamond150. During the first year of our program CDAC graduate student Wendy Mao, now at LANSCE/LANL, showed that the new diamond can be used to generate multimegabar pressures.151. Additional studies of the strength and annealing effects were also carried out this year by undergraduate summer intern Cheng Chin, who applied novel spectroscopic methods that had been pioneered in the Carnegie labs152. The team has also made colorless single-crystal diamonds, transparent from the ultraviolet to infrared wavelengths with their CVD process153, 154. Yogesh Vohra’s group at the University of Alabama-Birmingham continues to develop complementary designer anvil technology as part of CDAC. An isotopically enriched 13C homoepitaxial diamond layer of 6±1 microns thickness was grown on top of a brilliant cut diamond anvil by a microwave plasma chemical vapor deposition process for application as a pressure sensor. Figure 49 shows the isotopically enriched 13C beveled diamond anvil employed in high pressure experiments to 156 GPa. This isotopically enriched diamond tip was then used in conjunction with a natural isotopic abundance diamond anvil to generate high pressure on the sample. This group provided a calibration for the 13C Raman mode of this extremely thin epitaxial layer to 156 GPa using ruby fluorescence and the EOS of copper as secondary pressure standards. The nonlinear calibration of the 13C Raman mode pressure sensor is compared with similar calibrations of 12C

61 Raman edge and a good agreement is obtained. The Raman signal from the 13C epitaxial layer remained a distinct singlet to 156 GPa and pressure calibration is independent of sample mechanical strength or the diamond anvil geometry. The use of an even thinner layer would allow calibration further into the ultra high pressure regime where use of other optical sensors has proven to be difficult. High-Pressure Magnetic and Electronic Measurements – At Carnegie, Viktor Struzhkin 70 µ m has pioneered both high-pressure Kβ x-ray fluorescence155 and high-pressure Mössbauer Figure 49. The picture of a beveled spectroscopy156, 157, which complement magnetic diamond anvil with isotopically enriched susceptibility measurements. Measurements of Kβ x- 13C diamond thin layer on the surface. The central flat diameter of the diamond ray fluorescence in Fe3O4 (magnetite) to 80 GPa, show tip is 70 µµm, the culet diameter is 300 clear evidence of spin collapse at 60 GPa, compatible µm, and the bevel angle is 8.5˚. with available Mössbauer data158. Further improvements in nuclear inelastic resonant x-ray scattering [which has been used to study Fe159,160 and FeO161] allow measurements of the phonon density of states (Fe) or the partial phonon density of states (FeO) over a broad pressure range up to 150 GPa, including diluted systems. Similar measurements could give information on the valence band behavior in other correlated transition metal oxides. Struzhkin is also exploring the possibilities of combining laser heating, external heating, and low-temperature cryostat techniques at Sectors 3 and 16 at APS (Argonne) to extend the P-T range currently available for synchrotron Mössbauer techniques. The group is able to reach 200 GPa at 300 K, 2500 K at 90 GPa, using DAC technique. Low-temperature measurements have been conducted down to 10-20 K on the Bi57FeO3 single crystal sample in He pressure medium through the spin-crossover transition. Measurements of electrical resistance in a sample at high pressure are still very challenging, despite the progress made over the past several years. The Carnegie group is developing the technique to make good quality ohmic contacts to a sample in DAC using the focused ion beam (FIB) instrument at the Stanford Nanofabrication Facility (in collaboration with Professor Zhi-Xun Shen and graduate student Tanja Cuk of Stanford University). Nanofabrication techniques will allow better control over sample preparation and also will make possible much smaller samples suitable for multimegabar transport measurements. We also established a collaboration with the FIB facility at the University of Maryland, close to our Washington, DC campus (Fig. 50).

62 Figure 50. Preparation of diamond anvils for electrical resistivity measurements. Top: Focused Ion Beam deposition of the electrodes on the diamond anvils (University of Maryland). Bottom: Sample of a Bi-based high temperature superconductor on top of diamond anvil in contact with electrodes. Bottom left: sample before application of pressure. Bottom right: Sample in Ar pressure medium at 40 GPa.

At Carnegie, the Struzhkin group also combined optical spin resonance techniques, including time resolved Faraday rotation spectroscopy (TFRF), with DAC methods to investigate semiconductor quantum dots. These materials (QDs) are attractive candidates for scalable solid state implementations of quantum information processing based on their electron spin states. The detailed spin properties of QDs will strongly depend on the quantum confinement effect. For example, confined carriers in QDs are relatively decoupled from their dissipative environment as compared with systems of higher Figure 51. Top: TRFR dimensionality, such as quantum well, spectrum of 6.8nm CdSe which are expected to inhibit spin QDs at 1.0GPa (open relaxation processes and result in circles). The oscillatory extended spin coherence times. In behavior can be well addition, the electronic and excitonic described by the exponentially decaying Lande g-factors of QDs showed strong Larmor precession of dependence on their sizes. Such electron and exciton spins quantum confinement effects can be (red curve). Bottom: directly engineered by the reduction in pressure dependence of inter-atomic lattice constants through electronic and excitonic g- the application of hydrostatic pressure. factors of 4nm CdSe QDs The group has carried out revealing a sudden measurements to explore the effect of increase of g-factors at high pressure on spin coherence high pressure. dynamics on CdSe QDs, building up

63 towards investigations of new types of semiconductor quantum structures and some preliminary results were shown in Fig. 51. The mechanism of such a spin- pressure dependence is currently under investigation. The results of this research will not only be of great fundamental interest, enabling tuning spin properties to be closely correlated with structural changes, but they may also have direct implication of QD- based device applications by revealing the stability of spin properties under extreme conditions.

4.2 Facilities at Brookhaven, LANSCE, and Carnegie High-pressure IR measurements are becoming an increasingly important part of the CDAC research effort, and one of the techniques with which CDAC is growing the high-pressure material science community. The Carnegie group developed the field of high-pressure synchrotron IR micro- spectroscopy, which takes advantage of the enormous flux advantage of synchrotron radiation at long wavelengths relative to conventional broad band sources162, to address geophysical problems. Now, however, the recently upgraded U2A beamline at the NSLS, which is also managed and operated by this group with support from CDAC funds, features a custom-built long working distance IR microscope for diffraction-limited high P-T studies, and an optical/Raman grating spectrometer system with Ar, Kr, and Ti-sapphire lasers. Under CDAC, NNSA Labs have become 20% members of the U2A PRT. As needs arise, experiments can be carried out at beamline X17C and the newly created beamline X17B3 for high P-T diffraction. These diffraction facilities were previously managed by Carnegie under the NSF COMPRES consortium, but are now managed by the CARS group at Chicago. Both monochromatic and polychromatic diffraction can be performed with equipment that includes single-crystal and powder diffractometers, along with ruby luminescence systems for pressure measurement. The close working relationship between the CARS group at Chicago and the HPCAT group at Carnegie ensures that the facilities at X17 can be used at short notice. Both the x-ray and IR facilities are supported by a common sample preparation lab, and together they allow state-of-the-art diffraction and IR/Raman/optical spectroscopy to be performed on-site on the same samples.

Figure 52. Optical layout of the Synchrotron Infrared U2A beamline. Inset: U2A beamline optical hutch.

High P-T Neutron Scattering – Neutron-based probes have several unique advantages for the study of materials, particularly those of importance for stockpile stewardship, and are complementary to synchrotron x-ray and laser optical probes. A key part of the CDAC program from the beginning has been to support the development of high-pressure neutron scattering at LANSCE. Since that time, Rudy Wenk’s group at Berkeley has been working to develop standard procedures for direct image analysis of synchrotron diffraction data with the Rietveld method101, 102, 163. At

64 LANL, the group initially investigated texture changes taking place during phase transformations of hexagonal metals34, 35, 164. A significant portion of the thesis work of CDAC graduate student Jenny Pehl was concerned with advancing the methods of quantitative data analysis44, which she did in collaboration with LANSCE staff members Sven Vogel and Darrick Williams. Current CDAC graduate student Lowell Miyagi is continuing this work, and is addressing phase transformations under applied as well as residual stress. The α−β quartz transformation was originally used as a model system, with the results extended to other systems such as but also applying it to metals such as iron33, and important Earth materials such as magnesiowustite165, and silicate perovskites98. This research will continue in Year 4166-168. New CDAC academic partner Kanani Lee from New Mexico State University is currently utilizing the LANSCE facility to investigate the effects of pressure on rates of radioactive decay. The Spallation Neutron Source (SNS) at ORNL, which will be completed in 2007, will be the world’s most powerful neutron source, and CDAC is poised to take advantage of the facility’s capabilities. The Carnegie group and scientists at Stony Brook (led by John Parise) and ORNL (led by Christopher Tulk), are involved in the planning and construction of the dedicated high- pressure instrument (SNAP), which is one of the second set of instruments to be approved and funded. The project’s goal is to create new classes of instrumentation to utilize the extraordinary neutron flux of the SNS, develop state-of-the-art high-pressure devices for the facility, and advance the pressure range of neutron studies beyond present limits (tens of GPa) and improve sample size by orders of magnitude. The project is in Year 3 of its five-year plan, and the project is on schedule. At the third annual SNAP meeting held in April 2006 at the SNS, CDAC was represented by Carnegie’s Jian Xu, who presented the latest progress in neutron diffraction pressure cell development. CDAC academic partner Brent Fultz (Caltech) is also the PI on the ARCS spectrometer, which is also in the first group of instruments to be brought on line at the SNS.

Figure 53. Layout for SNAP, the high-pressure instrument and beamline being created at the Spallation Neutron Source. There is close collaboration with the high-pressure program at the Lujan Center at LANSCE, where tests of components are taking place

The Carnegie labs are continuing to upgrade existing facilities for use by the broader high pressure community. Upgraded spectroscopic facilities include improved capabilities for laser heating (Fig. 55) as well as those for Raman, IR and Brillouin measurements, all made possible through the CDAC grant. Support facilities such as the gas loading and diamond cell preparation

65 labs, have also undergone minor renovations over the last year under the CDAC grant. Additional developments were made in the Carnegie GHz ultrasonics laboratory (Fig. 54) and the CVD anvil facility, where a laser cutting and shaping system (Bettonville) has been installed. These improvements were supported by other grants and by Carnegie funds.

Figure 54. GHz-ultrasonic interferometer at Carnegie. Pictured clockwise from lower left are: 18-GHz mainframe sampling oscilloscope, 2- GHz RF generator, 6-GHz RF generator with internal pulse modulator, external pulse modulator (top), optical microscope for buffer- rod alignment, with diamond cell beneath objective, connected to the oscilloscope channel set. GHz- ultrasonic interferometry has been made possible through high-speed RF and microwave technologies developed during the telecom boom.

Figure 55. Facilities at Carnegie Top left: Maddury Somayazulu in the gas loading laboratory; top right: Jinfu Shu in the sample preparation laboratory; bottom left: Alexander Goncharov in the laser heating laboratory; bottom right: former CDAC predoctoral associate Shih- Shiue Ho (now at Case Western University) in the CVD diamond facility.

4.3 Commissioning Activities at HPCAT A significant portion of the CDAC budget has gone to obtaining a 30 percent share of member beam time at HPCAT, where commissioning activities are now nearing completion (Fig. 56). Insertion device beamlines ID-B (monochromatic powder diffraction) and ID-D (spectroscopy) have been operating in general user mode for nearly three years, and now the bending magnet beamlines have started accepting general user proposals through the APS system. Both BM-B and BM-D will focus on white beam diffraction, and both will have single crystal diffraction capabilities, in addition to serving as routine powder diffraction instruments. Stations BM-B, BM-D and ID-D are currently capable of handling cryostats for low-temperature work down to liquid helium temperatures, and station ID-B will soon have this capability as well. Laser heating is operating routinely in ID-B for high pressure diffraction measurements, and the long-term plan is to have laser heating available for x-ray spectroscopy experiments in ID-D as well. Online ruby/Raman systems are now being

66 installed on the bending magnet beamlines, and will soon be available on the ID beamlines as well. Now that there will be four simultaneously operating experimental stations at the HPCAT facility, a series of “Technical Briefs” detailing the capabilities of each of the stations are currently being prepared and will be posted on the CDAC web site so that the CDAC community will have access to updated information on each of the beamlines. This will help the research groups make optimal choices of the beamlines for their research projects. Reviews of the use of synchrotron facilities to study materials under extreme conditions, show the dramatic progress that has been made in this area of research over the past few years169, 170.

Figure 56. Facilities at HPCAT. Top left: 16ID-D; top right: 16ID-B; bottom left: Raman system; bottom right: laser heating system.

Peter Liermann, the beamline scientist at HPCAT who is leading the efforts at station BM- D, has commissioned the beamline as a white beam station but will add monochromaters for operating in large energy ranges in the near future. During commissioning on BM-D, a 5µm x 5 µm focal spot at the sample position has been routinely achieved. This group has carried out a number of studies at low temperatures (using a flow type liquid He cryostat) and plans to develop resistively heated diamond cell capabilities in the near future. The BM-D station has an on-line Raman system capable of measuring ruby luminescence, Raman and spectroradiometry without moving the sample. To accommodate the single crystal Laue techniques being developed, an on-line CCD is being integrated into the experimental setup. This will therefore be the only station that is capable of doing both white beam and monochromatic diffraction in powders and single crystals at extreme pressures and temperatures.

5. INTERACTIONS WITH NNSA/DP LABORATORIES 5.1 Overview One of the goals of CDAC is to provide access to the state-of-the-art facilities maintained by the groups of our academic partners, including synchrotron beamlines and the CDAC high-pressure

67 labs. CDAC members are encouraged to meet at the regularly scheduled HPCAT meetings at APS. There are also frequent visits to at National Labs, university nodes, or Carnegie for planning and coordination of efforts, integration of results, integration with ASC, and other stockpile stewardship programs. In all cases, travel support for graduate students has been provided from the core CDAC budget. The CDAC Summer School of Year 2, and the SSAAP Symposia in Year 1 (Albuquerque) and Year 2 (Las Vegas) SSAAP Symposium and Synergy of 21st Century High-Pressure Science and Technology Workshop (Section 3.5) of Year 3 discussed in Section 3.5 were highly successful ventures from the CDAC perspective, in that they in have all provided a forum in which possible research collaborations between graduate students from academic groups and NNSA Lab personnel were explored. • Experiments performed at HPCAT. The integrated HPCAT facility has all four of its experimental stations operating in general user mode, providing an excellent forum for people with many different areas of expertise to interact and initiate new research directions. Records of visits by NNSA Labs, CDAC academic partners, CDAC collaborators, and other users are listed below in Appendix II. • Technique development and training at Carnegie. During Year 3, a total of 42 different scientists came to Carnegie for periods of one day to several weeks, for training, sample preparation or to perform specific measurements in the high-pressure laboratories. Continuous technique development brings numerous people to Carnegie and serves as a focus for interactions among new and experienced researchers. This has been enhanced by the additional office and lab space provided by the Institution. • Visits to other facilities. The Carnegie synchrotron IR beamline (U2A) continues to be useful platform for interactions. Users from a variety of disciplines within the structure of CDAC have used the facility in the past year; lists of users at U2A are reported in Appendix II. The first SNAP workshop took place at LANL in April 2004. The second was held at the Spallation Neutron Source (SNS) in June 2005, and the latest was held at the SNS in April 2006. The meetings were attended by a number of CDAC academic partners, laboratory partners and collaborators. A number of new collaboration possibilities were also discussed. • Annual meetings and summer schools. The SSAAP annual meetings (March 2004, Albuquerque and August 2005, Las Vegas) have both been very well-attended and were highly productive as forums where CDAC partners, students, post-doctoral fellows, and staff were able to discuss research directions and initiate collaborative efforts. The 2005 CDAC Summer School and 2006 Synergy of 21st Century High-Pressure Science and Technology Workshop both brought a many graduate students together with CDAC partners and collaborators to discuss current directions in high pressure research of interest to stockpile stewardship science. • Experiments performed at NNSA/DP facilities. Proposed experiments at unique facilities in the NNSA/DP Labs will provide opportunities for scientific exchange in addition to training of students. The most notable example is the extensive use of LANSCE (Lujan Center) by CDAC students, postdoctoral fellows, and staff for high-pressure neutron scattering. An exciting initiative that emerged last year is the implementation of the new CVD diamond technology at Z and possible combined static/dynamic compression experiments there. CVD initiative with SNL began in Year 1 and continued into Year 2 with the award of an LDRD to the SNL for this work. In addition, planning began in Year 3 for laser shock experiments to be carried out at the APS (diffraction diagnostics) and U2A (infrared diagnostics). Currently, the projects are in the feasibility study stage, but work continues in an effort to bring the shock compression and static compression communities closer together, as stated in the CDAC mission. The CDAC website, located at http://www.cdac.gl.ciw.edu, serves as a primary source of information to the CDAC community and the public (Fig. 57). Featuring an array of scientific and technical developments, meeting announcements and links, beam time updates, the site serves as a “window to the world” of high-pressure research not only at CDAC, but throughout the US and

68 around the world. Lists of all of the CDAC partners, scientists, and collaborators, as well as records of all applicable publications and abstracts can also be found on the CDAC website and are updated regularly. Several times a month, a new research highlight is posted on the website, detailing information on new papers or research breakthroughs that have been supported by CDAC. Technical notes on high pressure techniques, briefs on HPCAT and U2A experiments, and leading references in the high pressure field are also being prepared for the broader high pressure community. 5.2 Academic Alliance and Laboratory Collaborations HPCAT Membership and Beam Time Allocation – Figure 57. Screen shot of the CDAC website, http://cdac.gl.ciw.edu HPCAT is a member-owned facility with ownership proportional to member contribution. Originally, 30% of the ownership was associated with stewardship science (H-Division of LLNL 10% and University of Nevada, Las Vegas, 20%). With construction completed at the facility, and with the implementation of CDAC Phase II, CDAC now is a 30% member based solely on the contribution from the core CDAC budget. This gives participating NNSA/DP Lab divisions and university partners representation on the HPCAT Council. Moreover, the stewardship science interest in HPCAT has been lifted from a minority to 75% (LLNL H-Division, 20%, CDAC, 30%, UNLV, 25%), thereby significantly increasing its ability to steer future developments at the facility. CDAC beam time is allocated based on the membership shares of each of the contributing members. At this point, all four experimental stations are fully commissioned and are accepting users through the General User Proposal program at the APS as well as from the member partners. For each beamline, the available shifts (three per day) during a beam time run period are totaled. After subtracting shifts for the General User Proposal (GUP) program of the APS (25% of beam time) and HPCAT time for technique development, beamline upgrades and staff research (25%), the available shifts are distributed among the HPCAT partners: Carnegie (25% of remaining time), CDAC (30%), LLNL H-Division (20%), University of Nevada-Las Vegas (25%). At this point, that means approximately 30-35 shifts per beamline in a typical run period (about 200 shifts total) will go to CDAC academic partners and their students, along with National Laboratory partners. During Year 3, 37 proposals were submitted for beam time through CDAC (26 from National Lab scientists and 11 from Academic Partners). Some of these proposals were granted beam time through the GUP process, allowing other users from within CDAC to benefit from the extra time allotted. In all cases, however, CDAC users who requested beam time were able to receive it. A detail of those who obtained beam time at HPCAT and the experiments they performed is given in Appendix II. In the future, it will most likely become necessary to award beam time to those proposals not awarded GUP time on a competitive basis. This will have the undesirable effect that good proposals will be denied

69 beam time, but that has not happened as yet. Having three experimental stations with diffraction capabilities will help keep beam time for the CDAC community quite available. LLNL – The history of collaborations between Carnegie and members of the LLNL PAT Directorate H-Division, currently headed by Robert Cauble has continued. Within CDAC, the partnership through HPCAT has been expanded to include each of the groups within the division, as indicated by the support of group leaders Giulia Galli (now at University of California – Davis), Neil C. Holmes, Andy K. McMahan, John A. Moriarty, Choong-Shik Yoo, and David A. Young. Graduate students Amy Lazicki (UC-Davis) and Zsolt Janei (University of Stockholm) have also been involved with CDAC-related projects through HPCAT. There are specific individuals representing a variety of Directorates with special interests in various CDAC science projects including Jagan Akella, William Durham (now at MIT), William Evans, and Joe Zaug. People working on collaborations within CDAC or have interacted closely with CDAC scientists include Bruce Baer, Sorin Bastea, Larry Boercker, Stanimir Bonev (now at Dalhousie University), Brian Bonner, Ricky Chau, Jonathan Crowhurst, Hynchae Cynn, Dan Farber, Larry Fried, Valentin Iota-Herbei, Jung-Fu-Lin (former Carnegie postdoctoral fellow and CDAC research scientist), Magnus Lipp, Riad Manaa, Andy McMahan, Jeff Nguyen, Tadashi Ogitsu, Jae-Hyun Park, Robert Rudd, and Eric Schwegler. CDAC is also actively involved in an initiative to develop new in situ x-ray probes in shock wave experiments; this effort involves G. W. (Rip) Collins, Damien Hicks, Jon Eggert, and Peter Cellers. LANL – The unique neutron facilities at the Lujan Center of LANSCE will be combined with expertise and instrumentation developments of the alliance members in order to develop high- pressure neutron diffraction and scattering capabilities for stockpile stewardship, Lujan Center director Alan Hurd, and scientists Yusheng Zhao, Zhongwu Wang, Robert P. Currier, Luke L. Daemen, Konstantin Lokshin, Junhua Luo, Donald D. Hickmott, Wendy L. Mao, Robert McQueeney, and Robert von Dreele are participating in projects supported by CDAC. In particular, Rudy Wenk’s group at Berkeley has been instrumental in developing texture analysis capabilities at HIPPO. In addition to neutron scattering, Yusheng Zhao’s group has been collaborating with CDAC in characterizing the new CVD diamond material developed at Carnegie. Other LANL collaborators and contacts include William Anderson, Robert Hixson, Rachel Hixon, David Moore, and David Schiferl. Brent Fultz has collaborated for several years with scientists at the Lujan Center and MST, and Dana Dlott interacts regularly with David Moore and David Funk. Other LANL scientists involved in ongoing collaborations with CDAC include Robert Sander, Dana Dattlebaum, Neal Chesnut, Joanna Casson, Lilliana Sanchez, Aaron Koskelo, Luc Daeman, Konstantin Lokshin, Christian Pantea, Jiang Qian, Zhongwu Wang, Didier Saumon, University of Arizona graduate student Kimberly Tait and postdoctoral associate Kirill Zhuravlev. SNL – There have been new initiatives proposed between the Carnegie group and George Samara’s group on piezoelectrics. At Carnegie, Ron Cohen and Muhetaer Ahart are collaborating with the SNL group on theory and experiments, respectively. Experiments carried out in Marcus Knudson’s group, including the isentropic compression experiments on the Z accelerator, provide a powerful complement to Carnegie’s DAC studies. The new diamond initiative with Daniel Dolan mentioned above has led to an LDRD grant at SNL and diamond substrates supplied to Carnegie for CVD diamond. The laser shock compression feasibility work carried out at BNL and mentioned above is providing another opportunity for interaction between the Lab and other parts of the CDAC community. Others investigating collaborative projects with CDAC personnel include Lalit Chabildas, Mike Furnish, and Tracy Vogler. Other Labs – There are also collaborators at other national facilities and centers. We interact closely with HiPSec at the University of Las Vegas – Reno, which is directed by Malcolm Nicol. HiPSec is also a NNSA-supported member of HPCAT. The in situ x-ray shock wave initiative at HPCAT involves Yogendra Gupta at the Washington State University Institute of Shock Physics. Groups directed by J. Robertson (ORNL), Christopher Tulk (ONRL), Gene Ice

70 (ORNL), Ercan Alp (APS), Chi-chang Kao (BNL), and Larry Carr (BNL). In addition to his work at LANSCE, Brent Fultz serves on the PAC for IPNS and is the PI for the ARCS spectrometer, to be one of the first five instruments at the SNS. As mentioned above, Russell J. Hemley and Ho- kwang Mao are co-PIs of the high-pressure instrument at the SNS (SNAP), which is in the second set of five beamlines to be built at the facility. CDAC provides a forum for interactions between NNSA/DP scientists and the wider academic community. Dudley R. Herschbach (Harvard University and Senior Fellow at Carnegie) is an active member of the CDAC community, as is Joe Feldman (formerly at the Naval Research Laboratory). Luca Lutterotti (Trento, Italy) and Siegfried Matthies (Dresden) continue to visit Berkeley to further develop the Rietveld texture code for quantitative analysis, and particularly refining it to study the elastic behavior of textured materials163, 171, 172. Notably, a large number of former students and post-doctoral fellows from CDAC academic groups have established new research programs in high-pressure science in academia. In the past three years, the following former post-doctoral fellows have set up teaching programs as new assistant professors (or the equivalent). Each of these young scientists is an active collaborator and is training new students. • Olga Degtyareva (University of Edinburgh; from Carnegie) • Mark Frank (Northern Illinois University; from Carnegie) • Eugene Gregoryanz (University of Edinburgh; from Carnegie) • Jennifer Jackson (California Institute of Technology; from Carnegie) • Steve Jacobsen (Northwestern University; from Carnegie) • Boris Kieffer (New Mexico State; from Princeton) • Jie Li (University of Illinois; from Carnegie) • Yanzhang Ma (Texas Tech; from Carnegie, now a CDAC academic partner) • Sebastien Merkel (Lille, France; from Berkeley) • Henry Scott (Indiana University South Bend; from Carnegie) • Anurag Sharma (Renssalear Polytechnic Institute; from Carnegie) • Sean Shieh (University of Western Ontario; from Princeton) • Yang Song (University of Western Ontario; from Carnegie) • Sergio Speziale (GFZ Potsdam, Germany; CDAC graduate student from Princeton, Postdoctoral fellow from Berkeley) • Sarah Stewart-Mukhopadhyay (Harvard; from Carnegie)

6. MANAGEMENT AND OVERSIGHT In this section, the management and oversight of CDAC, including the organizational structure and managerial activities of the past year, are reviewed. 6.1 CDAC Organization and Staff The Center is managed at Carnegie. The group leaders from each academic node of CDAC together with representatives from directorates (or divisions) at NNSA/DP Labs form an Executive Committee to direct and coordinate research, development, and access to facilities. The organizational structure of CDAC is shown in Fig. 58. CDAC directly supports the HPCAT facility and graduate students in the groups of the Academic Partners. Beam time at HPCAT and NSLS is awarded to the Academic Partners, National Lab Partners and University Collaborators. Coupled with beam time at Carnegie-managed facilities at the NSLS and interactions with National Lab Partners at its unique NNSA Lab facilities, CDAC has put in place a proven structure that promotes collaboration and interaction and a sharing of a broad range of unique experimental and theoretical capabilities.

71 Figure 58. CDAC organizational chart. The yellow area designates the principal components of CDAC. The oval area encompasses the three different goups of experimental facilities associated with CDAC.

At Carnegie the CDAC staff consists of Russell Hemley, Director, and Ho-kwang Mao, Associate Director. Members of the scientific staff at Carnegie that are involved directly with CDAC are • Ronald Cohen Computational Theory • Premyslaw Dera Crystallography • Yingwei Fei Geochemistry and Petrology • Joe Feldman Senior Visiting Fellow • Alexander Goncharov Optical Spectroscopy • Dudley Herschbach Senior Visiting Fellow • Burkhard Militzer Computational Theory • Viktor Struzhkin Electronic and Magnetic Properties Joe Feldman, from the Naval Research Laboratory, came to Carnegie in January of 2006 as a Senior Visiting Fellow. He is collaborating with CDAC researchers on theoretical studies of the properties of hydrogen at high pressures and temperatures. CDAC staff at Carnegie directly supported by the CDAC grant and Carnegie Institution matching funds (i.e., indirect cost return) are • Olga Degtyareva Research Scientist (now at the University of Edinburgh) • Stephen Gramsch CDAC Coordinator/Research Scientist • Morgan Phillips Administrative Assistant • Maddury Somayazulu Lab Manager/Research Scientist • Chang-Sheng Zha Lab Manager/Research Scientist In January of 2006, Olga Degtyareva took a position at the Centre for Science at Extreme Conditions at the University of Edinburgh, Scotland, joining former CDAC Research Scientist Eugene Gregoryanz. Chang-Sheng Zha joined CDAC as a Lab Manager/Research Scientist in April of 2006 and has been assisting Maddury Somayazulu with training CDAC visitors in state- of-the-art high pressure methods. Research Scientists at Carnegie working on CDAC-related projects include: • Szczesny Krasnicki (CVD diamond growth) • Jinfu Shu (sample preparation and powder diffraction)

72 • Jian Xu (neutron diffraction/cell development) • Chih-shiue Yan (CVD diamond growth) High-pressure facilities at NSLS are staffed by beamline scientists who support the CDAC effort. They are: • Quanzhong Guo (X17B) • Jingzhu Hu (X17C) • Zhenxian Liu (U2A, salary partially supported by CDAC) A number of predoctoral and postdoctoral associates at Carnegie supported by the Institution, other grants, or outside fellowships worked on CDAC tasks during Year 3. Their contributions also include training CDAC students and visitors in high-pressure experimental techniques: • Muhetaer Ahart (Aihaiti) • Pierre Beck • Jinyang Chen (now at Shanghai University) • Xiao-Jia Chen • Jennifer Ciezak • Yang Ding • Shih-Shian Ho (now at Case Western University) • Steven Jacobsen (now at Northwestern University) • Jennifer Jackson • Tim Jenkins • Joseph Lai • Yufei Meng • Sergey Tkachev At the end of 2005, Jinyang Chen returned to the School of Environmental and Chemical Engineering at Shanghai University, and Pierre Beck and Sergey Tkachev came to Carnegie from the ENS Lyon and the Hawaii Institute of Geophysics and Planetology, respectively, to begin work as Research Associates. Joseph Lai joined the CVD group from Florida State University. Shih-Shian Ho is now a doctoral student at Case Western University. In August 2006, Steven Jacobsen took a faculty position in the Department of Geological Sciences at Northwestern University. Jennifer Jackson will be starting as an assistant professor in Mineral Physics at the California Institute of Technology in November 2006. 6.2 CDAC Oversight In order to complement SSAAP oversight of CDAC, Steering and Advisory Committees have also been assembled to guide the research efforts in the long term. The tasks of the Steering Committee are to advise on monthly operational issues, attend monthly HPCAT meetings to serve as the member representatives of CDAC on the HPCAT council, and to serve as points of contact between CDAC and the participating divisions and directorates of the NNSA Labs. Members of the Steering Committee are: • Gilbert W. (Rip) Collins (LLNL) • Jon H. Eggert (LLNL) • Daniel Farber (LLNL) • David Funk (LANL) • Marcus Knudson (SNL) • David Schiferl (LANL) • Choong-shik Yoo (LLNL) • Joe M. Zaug (LLNL) • Yusheng Zhao (LANL)

73 The Advisory Committee is charged with assisting with strategic planning, providing guidance on scientific issues and programmatic needs, and acting as liaisons between CDAC and the NNSA Labs, other SSAAP Centers, and the broader academic community. The Advisory Committee consists of • Neil W. Ashcroft (Cornell) • Robert Cauble (LLNL) • Yogendra M. Gupta (WSU) • Alan Hurd (LANL) • Chi-chang Kao (Brookhaven) • Christian Mailhiot (LLNL) • George A. Samara (SNL) Members of the committees are invited to attend the monthly CDAC/HPCAT meeting and many interact frequently with the Director and Associate Director. Each of the members of the two CDAC committees has renewed their commitment to serving through Year 4 of the CDAC program. The 2005 Advisory Committee meeting was held on May 31, 2005 at HPCAT, in conjunction with the first CDAC Summer School. Six members of the Advisory Committee were present, along with Thomas Duffy and Dana Dlott (CDAC Academic Partners from Princeton University and University of Illinois, respectively) and Guoyin Shen from University of Chicago/GSECARS (now the HPCAT Project Manager). An overview of the activities from Year 2 was presented by Russell Hemley. Ho-kwang Mao presented a report on the scientific and technological developments that have occurred at HPCAT, and Stephen Gramsch presented a report on CDAC education and outreach. Discussions took place throughout and after the presentations. The advisory committee also considered the merits of the proposed expansion of CDAC to include four more academic partners, as well as an increased share of the HPCAT beam time. The reaction to the committee’s report to NNSA/SSAAP was extremely favorable, and at the beginning of Year 4, Phase II of the CDAC program was initiated. 6.3 Second Year Review On September 22, 2005, the Year 2 CDAC Review was held at the Advanced Photon Source, Argonne National Laboratory. A morning session of presentations outlining the mission and scientific and technical scope of the CDAC effort was followed by a tour of the APS and HPCAT facilities and a poster viewing session. In the afternoon, presentations by a representative from each of the National Labs discussed ongoing and planned collaborations, and presentations by each of the academic partners provided an overview of scientific progress made during the year at their institutions. Review Presentations: • Russell J. Hemley (Overview) • Ho-kwang Mao (HPCAT Scientific Overview) • Guoyin Shen (HPCAT Technical Overview) • Stephen Gramsch (Education, Training and Outreach) • Choong-shik Yoo (LLNL) • Dana Dattlebaum (LANL) • Jianzhong Zhang (LANL) • Daniel Dolan (SNL) • Brent Fultz (Caltech) • Dana Dlott (Illinois) • Tom Duffy (Princeton) • Dion Heinz (Chicago) • Yogesh Vohra (Alabama-Birmingham) • Hans-Rudolf Wenk (UC-Berkeley)

74 Review Panel: • Robert Hanrahan (DOE/NNSA) • Kirk Levedahl (DOE/NNSA) • Larry Fried (LLNL) • Jeff Yarger (Arizona State University) • Kathleen Alexander (LANL)

7. PLANS FOR YEAR 4 AND BEYOND 7.1 Scientific and Educational Focus As we move forward into Year 4 of the CDAC program, we have made an effort to focus on key materials with special properties at high pressure and temperature, and will continue to extend the results we have reported on here. Support of graduate students will continue to be a primary goal of the program, and will expand to include a total of 20 students in the whole of the Center in Years 4 and 5. We will also continue our education and outreach efforts to sponsor student travel (not just for those in CDAC, but also for our collaborators and other students with an interest in the field), to meetings of direct interest to the high pressure materials science community. For example, CDAC will cosponsor SMEC2007, held in Miami, by supporting student travel and organizing the scientific meeting (more information on SMEC2007 can be found on the internet at http://www.cesmec.fiu.edu). We also plan to hold another version of our summer school during the upcoming program year. Finally, we will continue to support beamline operations and upgrades at HPCAT (see upgrade proposal submitted to DOE-BES in Section 7.3 below) with the goal of keeping this facility available to our academic and laboratory partners. 7.2 Implementation of CDAC Phase II With the implementation of Phase II of the CDAC program in January 2006, we have been working to achieve the goals set out in the proposal which was enthusiastically endorsed by the CDAC Advisory Committee at its meeting in May 2005. The proposal included requests for the following: • Extension to a Five Year Cycle – The initial grant period for CDAC is now five years, and will end in January 2008. This extension has given us additional flexibility in planning the expansion of our partner groups and preparing for the future of our Center. • Increase in the number of partners – In addition to our original partner group, we have added groups from Texas Tech University (Yanzhang Ma), New Mexico State University (Kanani Lee), Arizona State University (Jeff Yarger), Florida International University (Surendra Saxena), and University of Nevada-Reno (Dhanesh Chandra). Each of these academic partners has recruited students to work on CDAC-related projects and is training these students. Many of these students have taken already taken advantage of our beam time allocation program. Due to differences in the costs of supporting students at these universities (tuition, stipends, and cost of living), this growth in the number of CDAC students is now accomplished with variable size awards. At New Mexico State University, Lee’s group has nearly finished building a new DAC laboratory, including four Syntek symmetric DACs, two preparation microscopes, a microdrill press, a micro-EDM and a Raman system. Ma’s group at Texas Tech is working in many areas, including exploring the effect of shear stress and strain on the phase transition in iron from the bcc to the hcp phase using synchrotron x-ray diffraction measurements in a rotational DAC, carrying out high pressure synchrotron x-ray diffraction experiments to investigate the properties of WS2 to 26 GPa at room temperature, and investigating the high-pressure behavior of MoS2, by synchrotron x-ray diffraction, to nearly 40 GPa at room temperature. At Arizona State University, the Yarger group has started preliminary work to characterize correlations between pressure-induced amorphization and polyamorphism in glassy systems as well as the enhanced glass-forming ability of materials at high pressure. Chandra and the group at the University of

75 Nevada – Reno plans to conduct a systematic study of the pressure-induced phase transformations in alkali metal complex hydrides. The compounds chosen for study include LiNH2, LiBH4, and NaBH4. The high pressure Raman spectroscopy studies will be performed at Carnegie. Synchrotron x-ray powder diffraction studies will be performed at Advanced Light Source high pressure beamline as well as at HPCAT, APS. The high pressure Raman spectroscopy data on LiNH2 has already been collected up to 25 GPa and the data analysis is ongoing. A high pressure sample preparation laboratory will be set up at Reno and DAC, EDM for gasket preparation, and other equipment will be acquired during the course of the year. Saxena’s group at Florida International University has been involved in the high pressure research community for a number of years. With their affiliation with CDAC, their work on hydrides and novel carbide and nitride systems will receive additional emphasis. The Saxena group also is working on high P-T calibration scales for the DAC, as well as methods for measuring the strength of materials using high pressure techniques. • Enlarge the CDAC share at HPCAT – Beam time at HPCAT has become extremely competitive with the growth in the field (see section 7.3.3 below). As of January 2006, the CDAC membership in HPCAT has now gone to 30%. We have divided this allocation equally between the National Lab and CDAC Academic groups. As we have now moved operations at HPCAT to four simultaneously operating hutches (three diffraction, one spectroscopy), the availability of beam time for all CDAC partner groups has grown significantly, and nearly all requests for beam time can be accommodated. • Additional CDAC support scientists – The success of pioneering studies and student and collaborator trainings at state-of-the-art facilities strongly depends upon on-site expert help and support. We have added a research scientist at Carnegie to help with increased efforts in the areas of student/visitor training and technique development. CDAC research scientists will also continue to assist CDAC users at HPCAT and NSLS. • Instrumentation development – We have continued our work on high P-T cells for neutron diffraction at LANSCE and SNAP, and on improving designs for resistively heated DACs. We are also now prepared to support feasibility studies and experimental collaboration at NSLS and HPCAT in the area of laser shock compression measurements coupled with synchrotron IR and x-ray diagnostics at these facilities. • Infrastructure at Carnegie facilities – The infrared spectroscopy beamline U2A at the NSLS, also supported in part by the NSF, is now fully supported for CDAC users. A number of CDAC students, postdoctoral associates, academic partners and laboratory partners have taken advantage of this highly productive and cutting-edge facility, including members of the CDAC shock compression community. In addition, a state-of-the-art videoconferencing facility for the Carnegie campus is in the planning stages. This capability will enhance communication between all nodes in the CDAC community. 7.3 HPCAT Upgrade Designed in 1998, HPCAT has pioneered the new-generation, high-pressure, synchrotron facility in which multiple techniques are integrated at a single sector for the advancement of multidisciplinary high-pressure research. The HPCAT program has been exceedingly successful in terms of scientific impact, technological advances, and user community development. To advance HPCAT for the second decade, the upgrade proposed the addition of four novel high-pressure synchrotron techniques that have recently become feasible and practical, as well as overall improvements of x-ray optics components in order to fully utilize the high brilliance source anticipated from the APS upgrade. For the high-pressure x-ray microprobe, the present spatial resolution limit of 3-5 µm will be improved by an order of magnitude to 200-300 nm. This upgrade is very timely for emerging high- pressure nanoscience. It may also enable the next breakthrough of maximum static pressure beyond the present record of 300-500 GPa. For the high-pressure inelastic x-ray scattering program, we

76 propose to add analyzers and detectors with100 meV energy resolution, which will greatly expand the present program of 1 eV resolution and open a large new research area for in-depth study of electronic energy levels at high pressures. For high-pressure x-ray diffraction, we will add a high- resolution diffractometer to improve the d-spacing resolution by an order of magnitude greater than the present state of the art. This upgrade will enable discoveries of numerous intricate, subtle structural changes accompanying important electronic, magnetic and phonon transitions. For the high-pressure laser-heating system, we will implement an innovative rotating optical system to allow laser heating and x-ray diffraction through different paths. As a result, the long-awaited study of high P-T deformation and rheological experiments will become possible. We will upgrade the 16ID x-ray optics train for higher brilliance. High-pressure x-ray studies are often brilliance-limited. Higher brilliance enables new, more powerful experiments, or leads to higher efficiency for existing techniques. We have thoroughly investigated and identified the key components that need to be strengthened, improved, or replaced for robust operation with maximum brilliance. Upgrading these components will immediately benefit the present operation as well as the proposed new high-pressure x-ray techniques. Moreover, the x-ray optics upgrade will provide sufficient margin for HPCAT to handle the anticipated higher brilliance (by one to two orders of magnitude) due to the source upgrades: first, a local enhancement at 16ID by adding the second undulator in the next couple of years, and then a facility-wide upgrade of the APS storage ring and lattice in the next decade. The unmatched brilliance, matching optics, and novel integrated techniques at HPCAT will provide the superior tools for the U.S. research community to lead the next level of development of high-pressure energy science in the foreseeable future. Most of the existing HPCAT x-ray optics components were designed eight years ago based on a single undulator. They need to be upgraded for the anticipated higher power and brilliance and for maximizing its capabilities. The proposed upgrade of high heat load components adopts recent APS designs, which exceed the requirements of double undulator operation and will also make the components likely survivable to the future APS upgrade project after 2014. The proposed Kohzu double crystal monochrometer is well proven in many APS sectors and other facilities and will enhance capabilities for tighter focus, maintaining precise positional and energy stability, and will greatly increase the efficiency in challenging x-ray spectroscopy experiments. The proposed replacement of silicon by large diamond crystals in the branching double crystal monochrometor is based on the proven performance of water-cooled diamond crystal under high heat load, and should provide much improved efficiency. Improved beamline optics and increased brilliance provide unique opportunities for new techniques dedicated for high pressure research: high resolution inelastic x-ray scattering, high resolution x-ray diffraction, and sub-micron probes. These techniques have been developed for samples at ambient conditions, but previously limited for high pressure research due to insufficient flux and efficiency. The design of the novel rotation laser heating technique is based on decades of experience, and is an extension of the existing laser heating system at HPCAT for rheology and elasticity studies at high P-T. 7.3.1 HPCAT Overview High Pressure Collaborative Access Team (HPCAT) was established by the U.S. high- pressure community to advance cutting-edge, multidisciplinary, high-pressure science and technology using synchrotron radiation (SR) at Sector 16 of the APS. HPCAT institution members, including Carnegie (the managing member), LLNL, University of Nevada at Las Vegas, University of Hawai’i, and CDAC, raised the initial 5-year (1999-2004), $15.45M, HPCAT construction/commission funds from federal and private sources. The current 5-year (2004-2009) HPCAT operation funds ($10.7M total) are supported jointly by DOE-NNSA ($6.9M) and DOE-BES ($3.8M grant to CIW, DE-FG02-99ER45775). This ~$2.1 M annual operation budget covers the personnel cost of HPCAT on-site team and operation expenses including costs for the beamline upkeep, user support, and a modest amount for instrumentation maintenance and improvement. The HPCAT facility has established four operating beamlines in nine hutches. Two beamlines are split in energy space from the insertion device (16ID) line, while the other two are

77 divided into two fans from the bending magnet (16BM) line. Through collaboration with other APS sectors and other facilities, an array of novel x-ray diffraction and spectroscopic techniques has been integrated with high pressure-temperature instrumentation at HPCAT. With a multidisciplinary approach and multi-institution collaborations, the high-pressure program at the HPCAT has been enabling myriad scientific breakthroughs in high-pressure physics, chemistry, materials, and Earth and planetary sciences as shown by the quality and quantity of its publications. With a string of successes beyond our initial expectations, we are now facing three new challenges. First, increasing demand of beam time at this highly desirable facility has generated an acute beam time shortage in the user community. Secondly, new synchrotrons abroad (e.g., DIAMOND at RAL) and newly upgraded high-pressure beamlines (e.g., at ESRF and SPring-8) have followed the HPCAT approach, but started with superior undulator source brilliance, and thus have an advantage over HPCAT. Thirdly, through the seven-year HPCAT experience, we have identified key components that need improvements and developed innovative ideas that could lead the next- level breakthroughs in high-pressure synchrotron instrumentation, but our routine operation budget does not contain sufficient funds for substantial improvements and new instrumentation. These three challenges can all be met by the proposed HPCAT upgrade. Specifically key optical components will be upgraded to eliminate the heat-load problem and improve the beam intensity, image quality, and stability on the samples by 5-10 times (with the present source brilliance) to bring it on par with the newest beamlines abroad. With the anticipated second undulator at Sector 16 and the overall APS upgrade in the horizon, the source brilliance of HPCAT will be unmatched in the next decade. We will optimize the integrated hardware and software operation system and effectively double the useful user beam time. We will implement a submicron x-ray probe, 100 meV-resolution inelastic x-ray spectrometer, high-resolution x-ray diffractometer, and rotation laser-heating system, thus enabling next generation advancement in high-pressure research. 7.3.2 Second Undulator at HPCAT and the APS Ring Upgrade The current insertion device at HPCAT is a standard APS type-A, 2.5-m undulator. The 5-m long straight section of each sector has sufficient room for two undulators. To maintain competitiveness and greatly improve efficiency, in the short term, APS has been upgrading the undulators to different designs and adding a second undulator to sectors based on need. Most high- pressure x-ray spectroscopy techniques are intensity-limited, and the increase in intensity can be translated directly into more efficient use of beam time, and will enable new experiments which have been impractical due to the lack of intensity. Furthermore, the two-undulator system will allow independent control of undulator parameters for two concurrently operating ID beamlines, thus nearly doubling our usable ID beam time. In the long term (in a decade), APS is planning new storage ring lattice and whole facility upgrade. Several options are being seriously considered as we prepare for this upgrade. Foremost amongst these is the energy-recovery LINAC (ERL) which may offer a revolutionary upgrade path that brings fourth-generation capabilities to the APS while preserving all that we have today and involving less user disruption than would a storage ring lattice upgrade. Having the second undulator together with the new APS innovative developments in the accelerator lattice and insertion devices, we anticipate an increase in x-ray radiation brilliance by more than an order of magnitude at HPCAT. The present HPCAT high heat load optics upgrade will also prepare us for the anticipated high brilliance. 7.3.3 Progress Report The HPCAT user program has been in operation since 2003. During that time, ~80% of the available user beam time (~200 days per calendar year) has been allocated to member users and to the APS general user proposals (GUPs) through a Web-based proposal system. The APS Beamtime Allocation Committee allocates the available time to the highest rated proposals by the Proposal- Review-Panels (PRPs). HPCAT allocates the remaining 75%, based on member user’s requests and

78 the need of instrumentation and technique commissioning and instrument setup/alignment. A total of 396 experiments have been performed since 2003 at HPCAT by over 350 scientists and students. Number of “person-visits” has reached 772 so far (Fig. 60). The experimental program is oversubscribed by a large number of highly rated beam time proposals submitted by talented scientists who publish successfully in top-rated journals and involve large numbers of students in their research. Oversubscription – The HPCAT sector has become heavily oversubscribed, which is illustrated by the GUP program at HPCAT. The oversubscription factor is defined to be the ratio of the number of shifts requested by GUP users to the number of shifts awarded (i.e., number available) to GUP users. The average oversubscription rate is 6.5 (if only counting first choice, it is 3.7) (Fig. 59). The oversubscription rate was temporarily relieved in the summer of 2006 due to the opening of 16BM-B and 16BM-D to general users, but it is expect to rise again very soon. Given the fact that we generally receive highly rated beam time proposals, this factor is too high above the warning line (~2) and eventually discourage users from submitting new proposals. The proposed HPCAT upgrade will greatly enhance the efficiency of beam time usage (by a factor of 10) and hence significantly increase available beam time. We do not anticipate a significant drop of the oversubscription rate, because the upgrade will also enhance the capabilities of existing techniques and introduce new capabilities, thus generating new science to be explored. The remaining challenge has been to balance the desire to give beam time to as many highly rated proposals as possible while providing sufficient beam time to each experiment to accomplish the intended goals.

Figure 59. Left: numbers of “person-visits” since 2003. Right: Oversubscription rate, the ratio of the number of shifts requested by GUP users to the number of shifts awarded, in the HPCAT user program. The HPCAT as the first choice is shown in red, with all choices in blue.

Publications – At the time of this upgrade, research at HPCAT has resulted in 164 publications, and the number is growing at an accelerated rate. All of these publications appeared in published journal articles or book sections. Twenty-one percent (21%) of these publications (35) appeared in “high profile journals” (Science, Nature, Proceedings of the National Academy Science, Physical Review Letters). In addition, five Ph.D. dissertations and two Master’s thesis were based in part on research conducted at HPCAT. APS maintains a publication database that includes all peer- reviewed publications from each APS sector. In 2005, HPCAT has the second largest number (next to GSECARS which is five years ahead of HPCAT, but HPCAT has higher number of high-profile papers) of publications (61) in the database of any of the non-protein crystallography sectors at the APS. In 2006 up to August, HPCAT has surpassed GSECARS publications in both quality and quantity. Most publications resulting from work at HPCAT include one or more HPCAT beamline scientists as co-authors.

79 Outreach and Community Development – Efforts are being made to ensure the HPCAT facility is responsive to the needs of the HPCAT members and the scientific community, and that the community is made aware of the capabilities of the facility. Some examples of the outreach efforts that we have undertaken include: High Pressure Committee (HPC) Meeting – The committee consists of all HPCAT member groups and a number of other leading groups in the U.S. The HPC meets regularly (3-4 times a year), reviews the progress of HPCAT, and provides advices on the developments. CDAC is a community outreach program promoting high-pressure “energy science”, and distributes all CDAC beam time (which is 30% of the total HPCAT member beam time) to high- pressure researchers at three national laboratories and 143 universities. General users who work on “energy science” (defined in the most liberal term as in the 2003 BESAC Report), therefore, has two channels to access HPCAT beam time: GUP and CDAC. Workshop on Rheology and Elasticity at Ultrahigh Pressure and Temperature – HPCAT co-organized the COMPRES-sponsored workshop held on Oct 21-23, 2005 at APS. Experts in DAC design, large volume high-pressure apparatus, and data analysis discussed the current state of ultra-high pressure deformation studies and future developments. Workshop on Synergy of 21st Century High-Pressure Science and Technology – The workshop was held April 29 through May 1, 2006 at the APS, which was organized by HPCAT and co-sponsored by CDAC and COMPRES. The meeting featured an extensive array of forward-looking presentations along with ample opportunities for discussions among the 112 scientists and 20 graduate students and postdoctoral researchers in attendance from the fields of physics, chemistry, materials science, biology, and earth and planetary sciences, from both academic institutions and the National Labs around the country. Argonne Neutron and X-ray Summer School – HPCAT has participated in this two week school since 2004. Students perform hands-on experiments using the micro-diffraction equipments at HPCAT beamlines. High Pressure Special Interest Group – HPCAT organizes a special interest group on high pressure techniques and applications at the APS. This group meets monthly. 7.3.4 HPCAT Facility Upgrade Project Supplementary Material Available For a complete description of the HPCAT proposed upgrade, please go to http://cdac.gl.ciw.edu/images/stories/HPCAT%20Overview.pdf .

80 APPENDIX I: CDAC Publications and Presentations for Year 3* A. CDAC Publications Ahart, M., A. Asthagiri, R. E. Cohen, J. L. Yarger, H. K. Mao and R. J. Hemley, Brillouin spectroscopy of relaxor ferroelectrics and metal hydrides, J. Mat. Sci. and Engineering A, in press. Ahart, M., A. Asthagiri, P. Dera, H. K. Mao, R. E. Cohen and R. J. Hemley, Single-domain electromechanical constants for Pb(Zn1/3Nb2/3)O3-4.5%PbTiO3 from micro-brillouin scattering, Appl. Phys. Lett., 88, 042908 (2006). Ahart, M., A. Asthagiri, Z. G. Ye, P. Dera, H. K. Mao, R. E. Cohen and R. J. Hemley, Brillouin scattering study of Pb(Mg1/3Nb2/3)O3, Phys. Rev. B, submitted. Ahart, M., R. E. Cohen, V. Struzhkin, E. Gregoryanz, D. Rytz, S. Prosandeev, R. J. Hemley and H. K. Mao, High-pressure scattering and x-ray diffraction study of the relaxor ferroelectric 0.96Pb(Zn1/3Nb2/3)O3 - 0.04PbTiO3, Phys. Rev. B, 71, 144102 (2005). Ahart, M., J. L. Yarger, K. M. Lantzky, S. Nakano, H. K. Mao and R. J. Hemley, High-pressure Brillouin scattering of amorphous BeH2, J. Chem. Phys., 124, 14502 (2006). Aksoy, R., Y. Ma, E. Selvi, M. C. Chyu, A. Ertas and A. White, Equation of state measurements of molybdenum disulfide, J. Phys. Chem. Solids, 67, 1914-1917 (2006). Amulele, G. M. and M. H. Manghnani, Compression studies of TiB2 using synchrotron x-ray diffraction and ultrasonic technique, J. Appl. Phys., 97, 023506 (2005). Angel, R., M. Bijak, J. Zhao, G. D. Gatta and S. D. Jacobsen, Static and ultrasonic observations on th effective hydrostatic limits of pressure media for high-pressure studies, J. Appl. Cryst., submitted. Atkinson, T. D., K. M. Chynoweth, V. Sarkar and P. Cervantes, Electronic band gap of FeS2 under pressure, Phys. Rev. B, submitted. Baer, B. J. and C. S. Yoo, Laser heated high density fluids probed by coherent anti-stokes Raman spectroscopy, Rev. Sci. Instrum., 76, 13907 (2005). Brglez, F., X. Y. Li, M. F. Stallmann and B. Militzer, Evolutionary and alternative algorithms: reliable cost predictions for finding optimal solutions to th LABS problem, Inform. Sci, in press. Brown, G. E., G. Calas and R. J. Hemley, Role of user facilities in Earth sciences research, Elements, 2, 23-30 (2006). Cai, Y. Q., H. K. Mao, P. C. Chow, J. S. Tse, Y. Ma, S. Patchkovskii, J. F. Shu, V. Struzhkin, R. J. Hemley, H. Ishii, C. C. Chen, I. Jarrige, C. T. Chen, S. R. Shieh, E. P. Huang and C. C. Kao, Ordering of hydrogen bonds in high-pressure low-temperature H2O, Phys. Rev. Lett., 94, 025502 (2005). Campbell, A. J., C. T. Seagle, D. L. Heinz, G. Y. Shen and V. Prakapenka, Partial melting in the iron-sulfur system at high pressure: A synchrotron x-ray diffraction study, Phys. Earth Planet. Inter., submitted. Caracas, R. and R. E. Cohen, Prediction of a new phase transition in Al2O3 at high pressures, Geophys. Res. Lett., 32, L06303 (2005). Caracas, R. and R. E. Cohen, Effect of chemistry on the stability and elasticity of the perovskite and post- perovskite phases in the MgSiO3-FeSiO3-Al2O3 system and implications for the lowermost mantle, Geophys. Res. Lett., 32, L16310 (2005). Chellappa, R. S., D. Chandra, S. A. Gramsch, R. J. Hemley, J. F. Lin and Y. Song, Pressure induced phase transformation in LiAlH4, J. Phys. Chem. B, 110, 11088-11097 (2006). Chen, J., H. Liu, C. D. Martin, J. B. Parise and D. J. Weidner, Crystal chemistry of NaMgF3 perovskite at high pressure and temperature, Am. Mineral., in press. Chen, J., Y. Wang, T. S. Duffy, G. Shen and L. Dobrzhinetskaya, eds. Advances in High-Pressure Technology for Geophysical Applications (Elsevier, Amsterdam, in press). Chen, X. J., H.-U. Habermeier, H. Zhang, G. Gu, M. Varela, J. Santamaria and C. C. Almasan, Metal-insulator transition above room temperature in the maximum colossal magnetoresistance manganite films, Phys. Rev. B, 72, 104403 (2005). Chen, X. J., B. Liang, Z. Wu, C. Ulrich, C. T. Lin, V. V. Struzhkin, R. J. Hemley, H. K. Mao and H. Q. Lin, Oxygen isotope effect in Bi2Sr2Can-1CunO2n+4+δ (n=1, 2, 3) Single Crystal, Phys. Rev. Lett., submitted. Chen, X. J., V. V. Struzhkin, Z. Wu, R. E. Cohen, S. Kung, H. K. Mao, R. J. Hemley and A. N. Christensen, Electronic stiffness of superconducting single crystal niobium nitride under pressure, Phys. Rev. B, 72, 094514 (2005).

* We list publications and presentations for 2005-2006, including all work supported fully or in part by CDAC. This list therefore includes work carried out at HPCAT by all of its members and users during this period.

81 Chen, X. J., V. V. Struzhkin, Z. Wu, M. Somayazulu, J. Qian, S. Kung, A. N. Christensen, Y. Zhao, R. E. Cohen, H. K. Mao and R. J. Hemley, Hard superconducting nitrides, Proc. Nat. Acad. Sci., 102, 3298-3201 (2005). Chen, X. J., V. V. Struzhkin, Z. G. Wu, R. J. Hemley, H. K. Mao and H. Q. Lin, Role of c-axis layering structure in cuprate superconductors, Phys. Rev. B, submitted. Chen, X. J., V. V. Struzhkin, Z. G. Wu, R. J. Hemley, H. K. Mao and H. Q. Lin, Unified picture of the oxygen isotope effect in cuprate superconductors, Phys. Rev. Lett., submitted. Chen, X. J. and H. Su, Electronic mechanism of critical temperature variation in RBa2CuO7- , Phys. Rev. B, 71, 0945112 (2005). Choudhury, N., Z. Wu, E. Walter and R. E. Cohen, Ab initio linear response and frozen phonons for the relaxor PbMg1/3Nb2/3O3, Phys. Rev. B, 71, 125134 (2005). Ciezak, J. A., T. A. Jenkins, Z. Liu and R. J. Hemley, High-pressure vibrational spectroscopy of energetic materials: Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), J. Phys. Chem., submitted. Correa, A. A., S. A. Bonev and G. Galli, Carbon under extreme conditions: phase boundaries and electronic properties from first principles calculations, Proc. Nat. Acad. Sci., 103, 1204-1208 (2006). Crowhurst, J. C., A. F. Goncharov, B. Sadigh, C. L. Evans, P. G. Morrall, J. L. Ferreira and A. J. Nelson, Synthesis and characterization of the nitrides of platinum and iridium, Science, 311, 1275-1278 (2006). Cumalioglu, I., A. Ertas, Y. Ma and T. T. Maxwell, State of the art: Hydrogen storage, Transaction of the ASME: Journal of Fuel Cell Science and Technology, submitted. Cumalioglu, I., Y. Ma, A. Ertas and T. T. Maxwell, High pressure hydrogen storage tank: A parametric design study, ASMA Journal of Pressure Vessel Technology, submitted. Cunningham, N., N. Velisavljevic and Y. K. Vohra, Crystal grain growth at alpha-uranium phase transformation in praseodymium, Phys Rev B, 71, 012108 (2005). Degtyareva, O., E. Gregoryanz, H. K. Mao and R. J. Hemley, Crystal structure of sulfur and selenium at pressures up to 160 GPa, High Press. Res., 25, 17-33 (2005). Degtyareva, O., E. Gregoryanz, M. Somayazulu, P. Dera, H. K. Mao and R. J. Hemley, Novel chain structures in group VI elements, Nature Materials, 4, 152-156 (2005). Degtyareva, O., E. Gregoryanz, M. Somayazulu, H. K. Mao and R. J. Hemley, Crystal structures of superconducting phases of S and Se, Phys. Rev. B, 71, 214104 (2005). Degtyareva, O., V. V. Struzhkin and R. J. Hemley, High-pressure Raman spectroscopy of commensurate and incommensurate phases of antimony, J. Phys.: Cond. Matter. Degtyareva, V. F., O. Degtyareva, H. K. Mao and R. J. Hemley, High-pressure behavior of CdSb: compound decomposition, new phase formation and amorphization, Phys. Rev. B, 73, 214108 (2006). Degtyareva, V. F., M. K. Sakharov, N. I. Novokhatskaya, O. Degtyareva, P. Dera, H. K. Mao and R. J. Hemley, Stability of Hume-Rothery phases in Cu-Zn alloys at pressures up to 50 GPa, J. Phys. Cond. Matt., 17, 7955-7962 (2005). Dera, P., C. T. Prewitt and S. D. Jacobsen, Structure determination by single-crystal x-ray diffraction at megabar pressures, J. Synch. Radiation, 12, 547-548 (2005). Ding, Y., P. Chow and H. K. Mao, Determining thermal diffuse scattering of vanadium with x-ray transmission scattering, Appl. Phys. Lett., 88, 061903 (2006). Ding, Y., H. Liu, M. Somayazulu, Y. Meng, J. Xu, C. T. Prewitt, R. J. Hemley and H. K. Mao, Zone-axis x-ray diffraction of single-crystal Fe1-xO under high pressure, Phys. Rev. B, 72, 174109 (2005). Ding, Y., H. Liu, J. Xu, C. T. Prewitt, R. J. Hemley and H. K. Mao, Zone-axis diffraction study of pressure induced inhomogeneity in single-crystal Fe1-xO, Appl. Phys. Lett., 87, 041912 (2005). Ding, Y., C. T. Prewitt and D. R. Veblen, Possible Fe/Cu ordering schemes in the 2a superstructure of bornite (Cu5FeS4), Am. Mineral, 90, 1265-1269 (2005). Ding, Y., C. T. Prewitt and D. R. Veblen, High-resolution transmission electron microscopy (HRTEM) study of 4a and 6a superstructure of bornite Cu5FeS4, Am. Mineral, 90, 1256-1264 (2005). Ding, Y., J. Xu, C. T. Prewitt, R. J. Hemley, H. K. Mao, J. A. Cowan, J. Zhang, J. Qian, S. C. Vogel, K. A. Lokshin and Y. Zhao, Variable pressure-temperature neutron diffraction of wustite (Fe1-xO): Absence of long-range magnetic order to 20 GPa, Appl. Phys. Lett., 86, DOI: 10.1063/1061.1852075 (2005). Dobrzhinetskaya, L. F., Z. Liu, P. Cartigny, J. Zhang, D. Tchkhetia, R. J. Hemley and H. W. Green II, Synchrotron infrared and Raman spectroscopy of microdiamonds from Erzgebirge, Germany, Earth Planet. Sci. Lett., 248, 325-334 (2006). Duffy, T., Synchrotron facilities and the study of deep planetary interiors, Reports on Progress in Physics, 68, 1811-1859 (2005). Errandonea, D., Y. Meng, M. Somayazulu and D. Häusermann, Pressure-induced alpha -> omega transition in titanium metal: a systematic study of the effects of uniaxial stress, Physica B, 355, 116-125 (2005).

82 Errandonea, D., J. Pellicer-Poers, F. J. Manjon, A. Segura, C. Ferrer-Roca, R. S. Kumar, O. Tschauner, P. Rodriguez-Hernandez, J. Lopez-Solano, S. Radescu, A. Mujica, A. Munoz and G. Aquilanti, High- pressure structural study of the scheelite tungstates CaWO4 and SrWO4, Phys. Rev. B, 72, 174106 (2005). Evans, W. J., M. J. Lipp, H. Cynn and C. S. Yoo, X-ray diffraction and Raman studies of beryllium: Static and elastic properties at high pressures, Phys. Rev. B, 72, 094113 (2005). Evans, W. J., M. J. Lipp, C. S. Yoo, H. Cynn, J. L. Herberg, R. S. Maxwell and M. F. Nicol, Pressure-induced polymerization of carbon monoxide: Disproportionation and synthesis of an energetic lactonic polymer, Chem. Materials, 18, 2520-2531 (2006). Fei, Y. and J. Li, Experimental constraints, in Treatise on Geochemistry, Vol. 2: The Mantle and Core (ed. R. W. Carlson) in press (Elsevier Science). Feng, Y., M. Somayazulu, R. Jaramillo, T. F. Rosenbaum, H. K. Mao, E. D. Isaacs and J. Hu, Energy dispersive x-ray diffraction of charge density waves via chemical filtering, Rev. Sci. Instrum., 76, 06391 (2005). Freiman, Y. A., S. M. Tret'yak, H. K. Mao and R. J. Hemley, Entropy-driven reentrant phase transitions in Even-J/Odd-J mixtures of linear rotors, J. Low Temp. Phys, 139, 765-772 (2005). Gasparov, L. V., D. Arenas, K. J. Choi, G. Guenthrodt, H. Berger, L. Forro, G. Margaritondo, V. V. Struzhkin and R. J. Hemley, Magnetite: Raman study of the high-pressure and low-temperature effects, J. Appl. Phys., 97, 10A922 (2005). Gavriliuk, A. G., V. V. Struzhkin, I. S. Lyubutin, M. I. Eremets, I. A. Trojan and V. V. Artemov, Equation of state and high pressure irreversible amorphization in Y3Fe5O12, JETP Lett., 83, 41-45 (2006). Gavriliuk, A. G., V. V. Struzhkin, I. S. Lyubutin, M. I. Hu and H. K. Mao, Phase transition with suppression of magnetism in BiFeO3 at high pressure, JETP Lett., 82, 243-246 (2005). Gey, N., M. Humbert, I. Lonardelli and H. R. Wenk, Texture changes during hcp - bcc phase transformation in titanium, Met. Trans., manuscript. Goncharov, A. F. and J. C. Crowhurst, Pulsed laser Raman spectroscopy in the laser-heated diamond anvil cell, Rev. Sci. Instrum., 76, 063905 (2005). Goncharov, A. F. and J. C. Crowhurst, Raman spectroscopy of hot compressed hydrogen and nitrogen: implications for the intramolecular potential, Phys. Rev. Lett., 96, 055504 (2006). Goncharov, A. F., J. C. Crowhurst, J. K. Dewhurst and S. Sharma, Raman spectroscopy of cubic nitride under extreme conditions of high pressure and temperature, Phys. Rev. B, 72, 100104 (2005). Goncharov, A. F., N. Goldman, L. E. Fried, J. C. Crowhurst, I. F. W. Kuo, C. J. Mundy and J. M. Zaug, Dynamic ionization of water under extreme conditions, Phys. Rev. Lett., 94, 125508 (2005). Goncharov, A. F. and E. Gregoryanz, Solid nitrogen at extreme conditions of high pressure and temperature, in Chemistry at Extreme Conditions (ed. R. Manaa) 241-268 (Elsevier Science, 2005). Goncharov, A. F. and R. J. Hemley, Probing hydrogen-rich molecular systems at high pressures and temperatures, Chem. Soc. Rev., doi:10.1039/b607523c (2006). Goncharov, A. F., M. R. Manaa, J. M. Zaug, R. H. Gee, L. E. Fried and W. B. Montgomery, Polymerization of formic acid under high pressure, Phys. Rev. Lett., 94, 065505 (2005). Goncharov, A. F., V. V. Struzhkin and S. D. Jacobsen, Reduced radiative conductivity of low-spin (Mg, Fe)O in the lower mantle, Science, 312, 1205-1208 (2006). Goncharov, A. F., V. V. Struzhkin, H. K. Mao and R. J. Hemley, Spectroscopic evidence for broken symmetry transitions in dense lithium up to megabar pressures, Phys. Rev. B, 71, 184114 (2005). Goncharov, A. F., J. M. Zaug, J. C. Crowhurst and E. Gregoryanz, Optical calibration of pressure sensors for high pressure and temperatures, J. Appl. Phys., 97, 094917 (2005). Gregoryanz, E., O. Degtyareva, M. Somayazulu, R. J. Hemley and H. K. Mao, Melting of dense sodium, Phys. Rev. Lett., 94, 185502 (2005). Gregoryanz, E., C. Sanloup, R. Bini, J. Kreutz, H. J. Jodl, M. Somayazulu, H. K. Mao and R. J. Hemley, On the ε-ζ transition of nitrogen, J. Chem. Phys., 124, 116102 (2006). Griffith, J. D., Structural and magnetic measurements on Au4V under high pressures to 60 GPa, Masters Thesis in Physics, University of Alabama at Birmingham, (2006). He, D. W. and T. S. Duffy, X-ray diffraction study of th static strenght of tungsten to 69 GPa, Phys. Rev. B, 73, 134106 (2006). Hemley, R. J., Erskine Williamson, extreme conditions, and the birth of mineral physics, Phys. Today, 59, 50-56 (2006). Hemley, R. J., A pressing matter, Phys. World, 19, 26-30 (2006). Hemley, R. J., Y. C. Chen and C. S. Yan, Growing diamond crystals by chemical vapor deposition, Elements, 1, 39-43 (2005). Hemley, R. J., H. K. Mao and V. V. Struzhkin, Synchrotron radiation and high pressure: new light on materials under extreme conditions, J. Synch. Radiation, 12, 135-154 (2005).

83 Hemley, R. J., V. V. Struzhkin and R. E. Cohen, Measuring high-pressure electronic and magnetic properties, in Treatise on Geophysics (Elsevier, in press). Ho, S. S., C. S. Yan, Z. Liu, H. K. Mao and R. J. Hemley, Prospects for large single crystal CVD diamonds, Industrial Diamond Review, 66, 28-32 (2006). Hope, K. M., Y. Vohra and T. LeBihan, Analysis of anistropic compression of uranium under high pressures: a computational and experimental overview, High Press. Res., 25, 235-242 (2005). Hu, J. Z., H. K. Mao, J. F. Shu, Q. Z. Guo and H. Liu, Diamond anvil cell radial x-ray diffraction program at the National Synchrotron Light Source, J. Phys. Cond. Matt., 18, S1091-1096 (2006). Huang, W., J. E. Patterson, A. S. Lagutchev and D. D. Dlott, Shock compression spectroscopy with high time and space resolution, AIP Confer. Proc., 845, 1265-1270 (2006). Ice, S. K., P. J. Eng, H. K. Mao, Y. Meng, M. Newville, M. Y. Hu and J. Shu, Probing of bonding changes in B2O3 glasses at high pressure with inelastic x-ray scattering, Nature Materials, 4, 851-854 (2005). Iezzi, G., Z. Liu and G. Della Ventura, Synchrotron infrared spectroscopy of synthetic Na(NaMg)Mg5Si8O22(OH)2 up to 30 GPa: Insights on a new amphibole high pressure polymorph, Am. Mineral, 91, 479-482 (2006). Ischia, G., H. R. Wenk, L. Lutterotti and F. Berberich, Quantitative rietveld texture analysis of zirconium from single synchrotron diffraction images, J. Appl. Cryst., 38, 377-380 (2005). Jackson, J. M., W. Sturhahn, G. Shen, J. Zhao, M. Hu, D. Errandonea, J. D. Bass and Y. Fei, A synchrotron Mössbauer spectroscopy study of (Mg,Fe)SiO3 perovskite up to 120 GPa, Am. Mineral, 90, 199-205 (2005). Jacobsen, S. D., Effect of water on the equation of state of nominally anhydrous minearls, in Water in Nominally Anhydrous Minerals (eds. H. Keppler and Smyth, J. R.) in press (Rev. Min. Geochem.). Jacobsen, S. D., S. Demouchy, D. J. Frost, T. B. Ballaran and J. King, A systematic study of OH in hydrous wadsleyite from polarized FTIR spectroscopy and single-crystal x-ray diffraction: oxygen sites for hydrogen storage in Earth's interior, Am. Mineral, 60, 61-70 (2005). Jacobsen, S. D., J. F. Lin, R. J. Angel, G. Shen, V. B. Prakapenka, P. Dera, H. K. Mao and R. J. Hemley, Single crystal synchrotron x-ray diffraction study of wüstite and magnesiowüstite at lower-mantle pressures, J. Synch. Radiation, 12, 557-583 (2005). Jacobsen, S. D., H. J. Reichmann, A. Kantor and H. A. Spetzler, A gigahertz ultrasonic interferometer for the diamond anvil cell and high-pressure elasticity of some iron-oxide minerals, in Advances in High- Pressure Techniques for Geophysical Applications (eds. J. Chen, Wang, Y., Duffy, T., Shen, G. and Dobrzhinetskaya, L.) 25-48 (Elsevier, Amsterdam, 2005). Jacobsen, S. D. and J. R. Smyth, Effect of water on the sound velocities of ringwoodite in the transition zone, in Earth's Deep Water Cycle (eds. S. D. Jacobsen and van der Lee, S.) in press (Am. Geophys. Union, Washington DC). Jiang, F., S. Speziale and T. S. Duffy, Single-crystal elasticity of brucite, Mg(OH)2, to 15 GPa by Brillouin scattering, Am. Mineral., in press. Kiefer, B. and T. S. Duffy, Finite element simulations of the laser-heated diamond anvil cell, J. Appl. Phys., 97, 114902 (2005). Kiefer, B., S. R. Shieh, T. S. Duffy and T. Sekine, Strength, elasticity, and equation of state of cubic silicon nitride (c-Si3N4) to 68 GPa, Phys. Rev. B, 72, 014102 (2005). Kim, H., A. Lagutchev and D. D. Dlott, Surface and interface spectroscopy of energetic materials: HMX and Estane, Propellants, Explosives, Pyrotechnics, 31, 116-123 (2006). Klug, D. D., J. S. Tse, Z. Liu and R. J. Hemley, Hydrogen-bonded dynamics and Fermi resonance in high- pressure methane-filled ice, J. Chem. Phys., in press. Kubo, A., B. Kiefer, G. Shen, V. Prakapenka, R. J. Cava and T. S. Duffy, Stability and equation of state of the post-perovskite phase of MgGeO3 to 2 Mbar, Geophys. Res. Lett., 33, L12S12 (2006). Kumar, R. S., A. L. Cornelius and M. Nicol, Structure of nanocrystalline ZnO up to 85 GPa, Synthetic Metals, in press. Kumar, R. S., A. L. Cornelius, Y. Shen, T. G. Kumary, J. Janaki, M. C. Valsakumar and M. Nicol, Structural behavior of non-oxide perovskite superconductor MgCNi3 at pressures up to 32 GPa, Physica B, 363, 190-195 (2005). Kumar, R. S., S. Rekhi, A. L. Cornelius and M. W. Barsoum, Compressibility of Nb2AsC to 41 GPa, Appl. Phys. Lett., 86, 111904 (2005). Lager, G. A., W. G. Marshall, Z. Liu and R. T. Downs, Re-examination of the hydrogarnet structure at high pressure using neutron powder diffraction and infrared spectroscopy, Am. Mineral, 90, 639-644 (2005). Lagutchev, A. S., J. E. Patterson, W. Huang and D. D. Dlott, Ultrafast dynamics of self-assembled monolayers under shock compression: Effects of molecular and substrate structure, J. Phys. Chem. B, 109, 5033- 5044 (2005).

84 Lazicki, A., B. Maddox, W. J. Evans, C. S. Yoo, A. K. McMahan, W. E. Pickett, R. T. Scalettar, M. Y. Hu and P. Chow, A new cubic phase of Li3N stability of the N3- ion to 200 GPa, Phys. Rev. Lett., 95, 165505 (2005). Lazicki, A. K., C. S. Yoo, W. J. Evans, W. E. Pickett and R. T. Scalettar, Pressure-induced antiflourite-to- anticotinnite phase transition in lithium oxide, Phys. Rev. B, 73, 184120 (2006). Lee, S. K., Microscopic origins of macroscopic properties of silicate melts and glasses at ambient and high pressure: Implications for melt generation and dynamic, Geochim. Cosmochim. Acta, submitted. Lee, S. K., P. J. Eng, H. K. Mao, Y. Meng, M. Newville, M. Y. Hu and J. Shu, Probing of bonding changes in B2O3 gasses at high pressure with inelastic x-ray scattering, Nature Materials, 4, 851-854 (2005). Lee, S. K., W. Fei, G. D. Cody and B. O. Mysen, The application of 170 and 27Al solid-state (3QMAS) NMR to structures of non-crystalline silicate at high pressure, in Advances in High-Pressure Techniques for Geophysical Applications (eds. J. Chen, Wang, Y., Duffy, T., Shen, G. and Dobrzhinetskaya, L.) 241-261 (Elsevier, Amsterdam, 2005). Lee, S. K., Y. Fei, G. D. Cody and B. O. Mysen, Structures of non-crystalline silicates at high pressure: 17O and 27Al solid-state (3QMAS) NMR study, in Frontiers in High Pressure Research (eds. J. Chen, Wang, Y., Duffy, T., Shen, G. and Dobrzhinetskaya, L.) in press (AGU). Liermann, H. P., A. K. Singh, B. Manoun, S. K. Saxena and C. S. Zha, Compressiion behavior of TaC0.98 under nonhydrostatic and quasi-hydrostatic pressure up to 76 GPa, Int. J. Refractory Metals Hard Matter, 23, 109-114 (2005). Lin, J. F., A. G. Gavriliuk, V. V. Struzhkin, S. D. Jacobsen, W. Sturhahn, M. Y. Hu, P. Chow and C. S. Yoo, Pressure-induced electronic spin transition of iron in magnesiowustite-(Mg,Fe)O, Phys. Rev. B, 73, 113107 (2006). Lin, J. F., E. Gregoryanz, V. V. Struzhkin, M. Somayazulu, H. K. Mao and R. J. Hemley, Melting behavior of H2O at high pressures and temperatures, Geophys. Res. Lett., 32, L11306 (2005). Lin, J. F., V. Struzhkin, S. D. Jacobsen, M. Y. Hu, P. Chow, J. Kung, H. Liu, H. K. Mao and R. J. Hemley, Spin transition of iron in magnesiowüstite in the Earth's lower mantle, Nature, 436, 377-380 (2005). Lin, J. F., V. V. Struzhkin, S. D. Jacobsen, G. Shen, V. B. Prakapenka, H. K. Mao and R. J. Hemley, X-ray emission spectroscopy with a laser-heated diamond anvil cell: a new experimental probe of the spin state of iron in the earth's interior, J. Synch. Radiation, 12, 637-641 (2005). Lin, J. F., W. Sturhahn, J. Zhao, G. Shen, R. J. Hemley and H. K. Mao, Nuclear resonant inelastic x-ray scattering and synchrotron mossbauer spectroscopy with laser-heated diamond anvil cells, in Advances in High-Pressure Technology for Geophysical Application (eds. J. Chen, Wang, Y., Duffy, T., Shen, G. and Dobrzhinetskaya, L.) 397-411 (Elsevier, Amsterdam, 2005). Lin, J. F., W. Sturhahn, J. Zhao, G. Shen, H. K. Mao and R. J. Hemley, Sound velocities of hot dense iron: Birch's law revisited, Science, 308, 1892-1894 (2005). Lin, T., W. Schildkamp, K. Brister, P. C. Doerschuk, M. Somayazulu, H. K. Mao and J. E. Johnson, The mechanism of high-pressure-induced ordering in a macromolecular crystal, Acta Cryst. D, 61, 737-743 (2005). Lipinska-Kalita, K. E., S. A. Gramsch, P. E. Kalita and R. J. Hemley, In situ raman scattering studies of high- pressure stability and transformation in the matrix of a nanostructured glass-ceramic composite, J. Raman Spectrosc., 36, 938-945 (2005). Lipinska-Kalita, K. E., P. E. Kalita and R. J. Hemley, β- to α- Ga2O3 phase transition in a nanocomposite material: In situ high pressure synchrotron x-ray diffraction investigations, Phys. Rev. B, submitted. Lipinska-Kalita, K. E., P. E. Kalita, D. M. Krol, R. J. Hemley, C. L. Gobin and Y. Ohki, Spectroscopic properties of Cr3+ ions in nanocrystalline glass-ceramic composites, J. Non-Crystalline Solids, 352, 524-527 (2006). Lipinska-Kalita, K. E., D. M. Krol, R. J. Hemley, G. Marioto, P. E. Kalita and Y. Ohki, Synthesis and characterization of metal-dielectric composites with copper nanoparticles embeded in a glass matrix: a multi technique approach, J. Appl. Phys., 98, 054301 (2005). Lipinska-Kalita, K. E., D. M. Krol, R. J. Hemley, G. Mariotto, P. E. Kalita and Y. Ohki, Temperature effects on luminescence properties of Cr3+ ions in heterophased oxide glass based nanostructured media, J. Appl. Phys., 98, 054302 (2005). Lipinska-Kalita, K. E., G. Mariotto, P. E. Kalita and Y. Ohki, Effects of high pressure on stability of the nanocrystalline LiAlSi2O6 phase of a glass-ceramic composite: A synchrotron x-ray diffraction study, Physica B, 365, 155-162 (2005). Lipp, M. J., W. J. Evans, B. Baer and C. S. Yoo, High-energy-density extended CO solid, Nature Materials, 4, 211-215 (2005). Lipp, M. J., W. J. Evans and C. S. Yoo, Hybrid Bridgman anvil design: An optical window for in-situ spectrsoscopy in large volume press, High Press. Res., in press. Lipp, M. J., W. J. Evans and C. S. Yoo, Cryogenic loading of large volume press for high-pressure experimentation and synthesis of novel materials, Rev. Sci. Instrum., 76, 53903 (2005).

85 Liu, H., J. Chen, J. Hu, C. D. Martin, D. J. Weidner, D. Häusermann and H. K. Mao, Octahedral tilting evolution and phase transition in orthorhombic NaMgF3 perovskite under pressure, Geophys. Res. Lett., 32, L04304 (2005). Liu, H., Y. Ding, M. Somayaulu, J. Qian, J. Shu, D. Häusermann and H. K. Mao, Rietvelt refinement study of the pressure dependence of the internal structural parameter u in the wurtzite phase of ZnO, Phys. Rev. B, 71, 212103 (2005). Liu, H., J. S. Tse, J. Hu, Z. Liu, L. Wang, J. Chen, D. J. Weidner, Y. Meng, D. Häusermann and H. K. Mao, Structural refinement of the high-pressure phase of aluminum trihydroxide: In situ high-pressure angle dispersive synchrotron x-ray diffraction and theoretical studies, J. Phys. Chem. B, 109, 8857- 8860 (2005). Liu, H., H. R. Wenk and T. S. Duffy, Rheoloy and elasticity studies at ultra-high pressures and temperatures, J. Phys. Cond. Matt., 18, S921-1103 (2006). Lonardelli, I., N. Gey, H. R. Wenk, S. Vogel and M. Humbert, In situ texture evolution during phase transformation in titanium alloys, Acta Mater., submitted. Lonardelli, I., H. R. Wenk, M. Goodwin and L. Lutterotti, Rietveld texture analysis from synchrotron images of dinosaur tendon and salmon scale, J. Synch. Radiation, 12, 354-360 (2005). Lucas, M. S., A. B. Papandrew, B. Fultz and M. Y. Hu, Cluster expansions of phonon densities of states: Effects of local structure in Fe-Cr, Phys. Rev. B, in preparation. Ma, Y., V. I. Levitas and J. Hashemi, X-ray diffraction measurements in a rotational diamond anvil cell, J. Phys. Chem. Solids, in press. Ma, Y., J. Liu, C. Gao, A. D. White, W. N. Mei and J. Rasty, High-pressure x-ray diffraction study of the giant dielectric constant material CaCu3Ti4O12: Evidence of stiff grain surface, Appl. Phys. Lett., 88, 191903 (2006). Ma, Y., E. Selvi, V. I. Levitas and J. Hashemi, Effect of shear strain on the α-ε phase transition of iron: a new approach in the rotational diamond anvil cell, J. Phys. Cond. Matt., 18, S1075-S1082 (2006). Majzlan, J., S. Speziale, T. S. Duffy and P. C. Burns, Single-crystal elastic properties of Alunite, KAl2(SO4)2(OH)6, Phys. Chem. Minerals, DOI:10.1007/s00269-00006-00104-z (2006). Manoun, B., S. K. Saxena and M. W. Barsoum, High pressure study of Ti4AlN3 to 55 GPa, Appl. Phys. Lett., 86, 101906 (2005). Mao, H. K., J. Badro, J. Shu, R. J. Hemley and A. K. Singh, Strength, anisotropy, and preferred orientation of solid argon at high pressures, J. Phys. Cond. Matt., 8, S963-S968 (2006). Mao, W. L., A. J. Campbell, D. L. Heinz and G. Shen, Phase relations of Fe-Ni alloys at high pressure and temperature, Phys. Earth Planet. Inter., 155, 146-151 (2006). Mao, W. L. and H. K. Mao, Ultrahigh-pressure experiment with a motor-driven diamond anvil cell, J. Phys. Cond. Matt., 18, S1069-S1103 (2006). Mao, W. L., H. K. Mao, Y. Meng, P. Eng, M. Y. Hu, P. Chow, Y. Q. Cai, J. Shu and R. J. Hemley, X-ray dissociation of H2O and formation of an O2-H2 alloy at high pressure, Science, in press. Mao, W. L., H. K. Mao, V. B. Prakapenka, J. Shu and R. J. Hemley, The effect of pressure on the structure and volume of ferromagnesian post-perovskite, Geophys. Res. Lett., 33, L12S02 (2006). Mao, W. L., H. K. Mao, W. Sturhahn, J. Zhao, V. B. Prakapenka, Y. Meng, Y. Fei and R. J. Hemley, Iron-rich post-perovskite and the origin of ultralow-velocity zones, Science, 312, 564-565 (2006). Mao, W. L., Y. Meng, G. Shen, V. B. Prakapenka, A. J. Campbell, D. L. Heinz, J. Shu, R. Caracas, R. E. Cohen, Y. Fei, R. J. Hemley and H. K. Mao, Iron-rich silicates in the Earth's D" Layer, Proc. Nat. Acad. Sci., 102, 9751-9753 (2005). Mao, W. L., V. V. Struzhkin, H. K. Mao and R. J. Hemley, Pressure-temperature stability of the van der Waals compound (H2)4CH4, Chem. Phys. Lett., 402, 66-70 (2005). Mao, Z., F. Jiang and T. Duffy, Single-crystal elasticity of zoisite, Ca2Al3Si3O12(OH), by Brillouin scattering, Am. Mineral., in press. Matthies, S., J. Pehl, H. R. Wenk, I. Lonardelli, L. Lutterotti and S. Vogel, Quantitive texture analysis of HIPPO TOF diffraction spectra, J. Appl. Cryst., 38, 462-475 (2005). Meng, Y., G. Shen and H. K. Mao, Double-sided laser heating system at HPCAT for in situ x-ray diffraction at high pressure and high temperatures, J. Phys. Cond. Matt., 18, S1097-S1103 (2006). Merkel, S., A. Kubo, L. Miyagi, S. Speziale, T. S. Duffy, H. K. Mao and H. R. Wenk, Plastic deformation of MgGeO3 post-perovskite at lower mantle pressures, Science, 311, 644-646 (2006). Merkel, S., J. Shu, P. Gillet, H. K. Mao and R. J. Hemley, X-ray diffraction study of the single crystal elastic moduli of ε- Fe up to 30 GPa, J. Geophys. Res., 110, B05201 (2005). Militzer, B., First principles calculations of shock compressed fluid helium, Phys. Rev. Lett., in press. Militzer, B. and R. J. Hemley, Solid oxygen takes shape, Nature, 443, 150-151 (2006).

86 Militzer, B., E. L. Pollock and D. Ceperley, Path integral Monte Carlo calculation of the momentum distribution of the homogeneous electron gas at finite temperature, Phys. Rev. B, submitted. Miyagi, L., S. Merkel, T. Yagi, N. Sata, Y. Ohishi and H. R. Wenk, Quantative Reitvelt texture analysis of CaSiO3 perovskite deformend in a diamond anvil cell, J. Phys. Cond. Matt., 18, S995-1005 (2006). Mora, A. E., J. W. Steeds, J. E. Butler, C. S. Yan, H. K. Mao and R. J. Hemley, Direct evidence of interaction between dislocations and point defects in diamond, Phys. Stat. Sol. (a), 202, R69-R71 (2005). Mora, A. E., J. W. Steeds, J. E. Butler, C. S. Yan, H. K. Mao, R. J. Hemley and D. Fisher, New direct evidence of point defects interacting with dislocations and grain boundaries in diamond, Phys. Stat. Sol., 202, 2943-2949 (2005). Okuchi, T., G. D. Cody, H. K. Mao and R. J. Hemley, Hydrogen bonding and dynamics of methanol by high- pressure diamond anvil cell NMR, J. Chem. Phys., 122, 244509 (2005). Okuchi, T., R. J. Hemley and H. K. Mao, Radio frequency probe with improved sensitivity for diamond anvil cell nuclear magnetic resonance, Rev. Sci. Instrum., 76, 026111 (2005). Okuchi, T., H. K. Mao and R. J. Hemley, A new gasket material for higher resolution in NMR in diamond anvil cells, in Advances in High-Pressure Technology for Geophysical Applications (eds. J. Chen, Wang, Y., Duffy, T., Shen, G. and Dobrzhinetskaya, L.) 503-509 (Elsever, Amsterdam, 2005). Okuchi, T., M. Takigawa, J. Shu, H. K. Mao, R. J. Hemley and T. Yagi, Fast molecular transport in hydrogen hydrates by high-pressure diamond anvil cell NMR, Phys. Rev. Lett., submitted. Papandrew, A. B., M. S. Lucas, R. Stevens, B. Fultz, M. Y. Hu, I. Halevy, R. E. Cohen and M. Somayazulu, Absence of magnetism in hcp iron-nickel at 11 K, Phys. Rev. Lett., 97, 087202 (2006). Patterson, J. E. and D. D. Dlott, Ultrafast shock compression of self-assembled monolayers: A molecular picture, J. Phys. Chem. B, 109, 5045-5054 (2005). Patterson, J. E., A. Lagutchev, W. Huang and D. D. Dlott, Ultrafast dynamics of shock compression of molecular monolayers, Phys. Rev. Lett., 94, 015501 (2005). Patterson, J. E., A. S. Lagutchev, S. A. Hambir, W. Huang, H. Yu and D. D. Dlott, Time and space resolved studies of shock compression molecular dynamics (invited), Shock Waves, 14, 391-402 (2005). Pehl, J. and H. R. Wenk, Evidence for regional Dauphine twinning in quartz from the Santa Rosa mylonite zone in Southern California: A neutron diffraction study, J. Struct. Geol., 27, 1741-1749 (2005). Qiu, W., P. A. Baker, N. Velisavljevic, Y. K. Vohra and S. T. Weir, Calibration of an isotopically enriched carbon- 13 layer pressure sensor to 156 GPA in a diamond anvil cell, J. Appl. Phys., 99, 046906 (2006). Reichmann, H. J. and S. D. Jacobsen, Sound velocities and elastic constants of ZnAl2O4 spinel and implications for spinel-elasticity systematics, Am. Mineral., 91, 1049-1054 (2006). Runge, C. E., A. Kubo, B. Kiefer, Y. Meng, V. Prakapenka, G. Shen, R. J. Cava and T. S. Duffy, Equation of state of MgGeO3 perovskite to 65 GPa: Comparison with the post-perovskite phase, Phys. Chem. Minerals, submitted. Santoro, M., J. F. Lin, V. V. Struzhkin, H. K. Mao and R. J. Hemley, In situ Raman spectroscopy with laser- heated diamond anvil cells, in Advances in High-Pressure Technology for Geophysical Applications (eds. J. Chen, Wang, Y., Duffy, T., Shen, G. and Dobrzhinetskaya, L.) 413-423 (Elsevier, Amsterdam, 2005). Scott, H. P., Z. Liu, R. J. Hemley and Q. Williams, High pressure infrared spectra of talc and lawsonite, Am. Mineral., submitted. Seagle, C. T., A. J. Campbell, D. L. Heinz, G. Shen and V. B. Prakapenka, Thermal equation of state in Fe3S and implications for sulfur in Earth's core, J. Geophys. Res. - Solid Earth, 111, B06209 (2006). Selvi, E., Y. Ma, R. Aksoy, A. Ertas, A. White and S. Jagdev-Singh, High pressure x-ray diffraction study of tungsten disulfide, J. Phys. Chem. Solids, 67, 2183-2186 (2006). Shahar, A., W. Bassett, H. K. Mao, I. M. Chou and W. L. Mao, The stability and Raman spectra of ikaite, CaCo3 6H2O, at high pressure and temperature, Am. Mineral., 90, 1835-1839 (2005). Sharma, A., G. D. Cody, J. Scott and R. J. Hemley, Molecules to microbes: in-situ studies of organic systems under hydrothermal conditions, in Chemistry Under Extreme Conditions (ed. R. Manaa) 83-108 (Elsevier Science, 2005). Shieh, S. R., T. S. Duffy, A. Kubo, G. Shen, V. B. Prakapenka, N. Sata, K. Hirose and Y. Ohishi, Equation of state of the post-perovskite phase synthesized from a natural (Mg,Fe)SiO3 orthopyroxene, Proc. Nat. Acad. Sci., 103, 644-646 (2006). Shieh, S. R., T. S. Duffy and G. Shen, X-ray diffraction study of phase stability in SiO2 at deep mantle conditions, Earth Planet. Sci. Lett., 235, 273-282 (2005). Shieh, S. R., A. Kubo, T. S. Duffy, V. B. Prakapenka and G. Shen, High-pressure phases in SnO2 to 117 GPa, Phys. Rev. B, 73, 014105 (2006). Singh, A. K., H. P. Liermann, S. K. Saxena and H. K. Mao, Compressive strength of gold crystallites under pressure up to 60 GPa: observation of crystallite size effect, J. Appl. Phys., submitted.

87 Singh, A. K., H. P. Liermann, S. K. Saxena, H. K. Mao and S. U. Devi, Nonhydrostatic compression of gold powder to 60 GPa in a diamond anvil cell: estimation of compressive strength from x-ray diffraction data, J. Phys. Cond. Matt., 18, S969-S978 (2006). Smyth, J. R. and S. D. Jacobsen, Nominally anhydrous minerals and Earth's deep water cycle, in Earth's Deep Water Cycle (eds. S. D. Jacobsen and van der Lee, S.) in press (Am. Geophys. Union Monography). Song, Y., R. J. Hemley, H. K. Mao and D. R. Herschbach, Nitrogen-containing molecular systems at high pressures and temperatures, in Chemistry under Extreme Conditions (ed. R. Manaa) 189-222 (Elsevier Science, 2005). Song, Y., Z. Liu, R. J. Hemley, H. K. Mao and D. R. Herschbach, High-pressure vibrational spectroscopy of sulfur dioxide, J. Chem. Phys., 122, 174511 (2005). Speziale, S., F. Jiang and T. Duffy, Compositional dependecne of the elastic wave velocities of mantle mineras: Implications for seismic properties of mantle rocks, in Structure, Composition, and Evolution of Earth's Mantle (eds. J. D. Bass, Van Der Hilst, R., Matas, J. and Trampert, J.) 303-323 (AGU Monograph Series, 2005). Speziale, S., A. Milner, V. E. Lee, S. M. Clark and M. P. Pasternak, Iron spin trasnition in Earth's mantle, Proc. Nat. Acad. Sci., 102, 17918-17922 (2005). Speziale, S., L. Miyagi and H. R. Wenk, Strain distribution in a diamond anvil cell: Deformation of copper, J. Phys. Cond. Matt., 18, S1007-1020 (2005). Speziale, S., S. R. Shieh and T. S. Duffy, High-pressure elasticity of calcium oxide: A comparison between Brillouin scattering and radial x-ray diffraction, J. Geophys. Res., 111, B02203 (2006). Struzhkin, V. V., A. F. Goncharov, R. Caracas, H. K. Mao and R. J. Hemley, Synchrotron infrared spectroscopy of the pressure induced insulator-metal transitions in glassy As2S3 and As2Se3, Phys. Rev. Lett., submitted. Struzhkin, V. V., H. K. Mao, J. F. Lin, R. J. Hemley, J. S. Tse, Y. Ma, M. Hu, P. Chow and C. C. Kao, Valence band x-ray emission spectra of compressed germanium, Phys. Rev. Lett., 96, 137402 (2006). Strzhemechny, M. A., Anisotropic interactions between HD molecules, Phys. Rev. B, 73, 174301 (2006). Tait, K. T., F. C. Hawthrne, J. D. Grice, L. Ottolini and V. K. Nayak, Dellaventuraite, NaNa2(MgMn3/2+Ti4+Li)Si8O22O2, a new anhydrous amphibole from the Kajlidongri Manganese Mine, Jhabua District, Madhya Pradesh, India, Am. Mineral., 90, 304-309 (2005). Teredesai, P., D. Anderson, N. Hauser and J. L. Yarger, Infrared spectroscopy of germanium dioxide (GeO2) glas at high pressure, Phys. Chem. Glasses, 46, 345-349 (2005). Terekhov, S. V., E. D. Obstratzova, H. D. Hochheimer, P. Teredesai, J. L. Yarger and A. V. Osadchy, Raman scattering as a probe of the electronic structure of single-wall carbon nanotubes under high pressure, AIP Confer. Proc., 786, 166-169 (2005). Tommaseo, C., S. Speziale, S. Merkel, H. R. Wenk and J. Devine, DAC investigations of plasticity and elasticity in the MgO-FeO series, Phys. Chem. Minerals, 33, 84-87 (2006). van Westrenen, W., M. R. Frank, Y. Fei, J. M. Hanchar, R. J. Finch and C. S. Zha, Compressibility and phase transition kinetics of lanthanide-doped zircon, J. Amer. Ceramic Soc., 88, 1345-1348 (2005). van Westrenen, W., J. Li, Y. Fei, M. R. Frank, H. Hellwig, T. Komabayashi, K. Mibe, W. G. Minarik, J. A. Van Orman, H. C. Watson, K. Funakoshi and M. W. Schmidt, Thermoelastic properties of (Mg0.64Fe0.36)O ferropericlase based on in situ x-ray diffraction to 26.7 GPa and 2173 K, Phys. Earth Planet. Inter., 151, 163-176 (2005). van Westrenen, W., J. Li, Y. Fei, W. Minarik, J. V. Orman, T. Komabayashi and K. Funakoshi, In situ determination of magnesiowustite thermal equation of state to 25 GPa and 2073 K, Phys. Chem. Minerals, submitted. Velisavljevic, N., Y. K. Vohra and S. T. Weir, Simultaneous electrical and x-ray diffraction studies on neodymium metal to 152 GPa, High Press. Res., 25, 137-144 (2005). Wan, J. T. K., T. S. Duffy, S. Scandolo and R. Car, First principles study of density, viscosity, and diffusion coefficients of liquid MgSiO3 at conditions of the Earth's deep mantle, J. Geophys. Res., in press. Wang, Z., Y. Zhao, C. S. Zha, Q. Xiue, R. T. Downs, R. G. Duan, R. Caracas and R. J. Hemley, X-ray induced synthesis of 8H diamond, Science, submitted. Wang, Z. W., L. L. Daemen, Y. Zhao, C. S. Zha, R. T. Downs, X. Wang, Z. L. Wang and R. J. Hemley, Morphology-tuned surface structure, mechanical stability, and tranformation mechanism in wurtzite- type ZnS nanobelts, Nature Materials, 4, 922-927 (2005). Wenk, H. R., eds. Neutron Scattering in Earth Sciences. (Amer. Mineral. Soc., 2006). Wenk, H. R., I. Huensche and L. Kestens, In-situ observation of texture changes during the bcc-fcc phase transformation in ultralow carbon steel, Metall. Trans., submitted. Wenk, H. R., G. Ischia, N. Nishiyama, Y. Wang and T. Uchida, Texture development and deformation mechanisms in ringwoodite, Phys. Earth Planet. Inter., 152, 191-199 (2005).

88 Wenk, H. R., I. Lonardelli, S. Merkel, L. Miyagi, J. Pehl, S. Speziale and C. Tommaseo, Deformation textures produced in diamond anvil experiments, analyzed in radial diffraction geometry, J. Phys. Cond. Matt., 18, S933-947 (2006). Wenk, H. R., I. Lonardelli, E. Rybacki, G. Dresen, N. Barton, H. Franz and G. Gonzalez, Dauphine twinning and texture memory in polycrystalline quartz. Part 1: Experimental deformation of novaculite, Phys. Chem. Minerals, in press. Wenk, H. R., I. Lonardelli, S. C. Vogel and J. Tullis, Dauphine twinning as evidence for an impact origin of preferred orientation in quartzite: An example from Vredefort, South Aftrica, Geology, 33, 273-276 (2005). Wenk, H. R., S. Speziale, A. K. McNamera and E. J. Garnero, Modeling anisotropy development in the lower mantle, Earth Planet. Sci. Lett., 245, 302-314 (2006). Wu, Z., X. J. Chen, V. V. Struzhkin and R. E. Cohen, Trends in elastic and electronic structure of transition- metal nitrides and carbides from first principles, Phys. Rev. B, 71, 214103 (2005). Wu, Z. and R. E. Cohen, Pressure-induced anomalous phase transitions and colossal enhancement of piezoelectricity in PbTiO3, Phys. Rev. Lett., 95, 037601 (2005). Xie, X., M. E. Minitti, M. Chen, H. K. Mao, D. Wang, J. Shu and Y. Fei, Tuite, a new high-pressure phosphate mineral, Diqiu Hauxue (Geochimica), 32, 566 (2005). Yang, J., W. Bai, H. Rong, Z. Zhang, Q. Fang, B. Yang, T. Li, Y. Ren, S. Chen, J. Hu, J. Shu and H. K. Mao, Discovery of Fe2P alloy in garnet peridotite from the Chinese Continental Scientific Drilling Project (CCSD) main hole, Acta Petrologica Sinica, 21, 271-276 (2005). Yoo, C. S., High pressure materials research: Novel extended phase of molecular triatomics, in Chemistry in Extreme Conditions (ed. R. Manna) 165-189 (Elsevier, 2005). Yoo, C. S., B. Maddox, J. H. P. Klepeis, V. Iota, W. Evans, A. McMahan, M. Hu, P. Chow, M. Somayazulu, D. Hausermann, R. T. Scalettar and W. E. Pickett, First-order isostructural Mott transition in highly- compressed MnO, Phys. Rev. Lett., 94, 115502 (2005). Yoshimura, Y., H. K. Mao and R. J. Hemley, Direct transformation of ice VII' to low-density amorphous ice, Chem. Phys. Lett., 420, 503-506 (2006). Yoshimura, Y., S. T. Stewart, M. Somayazulu, H. K. Mao and R. J. Hemley, High-pressure x-ray diffraction and Raman spectroscopy of Ice VIII, J. Chem. Phys., 124, 024502 (2006). Yoshimura, Y., S. T. Stewart-Mukhopadhyay, H. K. Mao and R. J. Hemley, In situ Raman spectroscopy of low P- T transformations of H2O, J. Chem. Phys., submitted. Yoshimura, Y., S. T. Stewart-Mukhopadhyay, M. Somayazulu, H. K. Mao and R. J. Hemley, X-ray and Raman study of the high-pressure behavior of ice VIII, J. Chem. Phys., 124, 024502 (2006). Young, A. F., C. Sanloup, E. Gregoryanz, S. Scandolo, R. J. Hemley and H. K. Mao, Synthesis of novel transition metal nitrides IrN2 and OsN2, Phys. Rev. Lett., 96, 155501 (2006). Zhang, H., B. Chen, B. Gilbert and J. F. Banfield, Kinetically controlled formation of a novel nanoparticulate ZnS with mixed cubic and hexagonal stacking, J. Mater. Chem., 16, 249-254 (2006). Zhao, Y., H. Xu, L. L. Daemen, K. A. Lokshin, W. L. Mao, J. Luo, R. P. Currier and D. D. Hickmott, High-P/low- T neutron scattering of hydrogen inclusion compounds - progress and prospects, Proc. Nat. Acad. Sci., submitted. Zotov, N., W. Kockelmann, I. Mitov, D. Paneva, R. D. Vassileva and I. K. Bonev, Structure and cation order in magnanilvaite: A combined x-ray-diffraction, neutron-diffraction and mössbauer study, The Canadian Mineralogist, 43, 1043-1053 (2005).

89 B. CDAC Presentations Ahart, M., A. Ashthagiri, R. J. Hemley and R. E. Cohen, Micro-spectroscopic study of relaxor ferroelectrics, Fundamental Physics of Ferroelectrics 2005 (Williamsburg, VA, February 6-9, 2005). Ahart, M., A. Asthagiri, R. E. Cohen, J. L. Yarger, H. K. Mao and R. J. Hemley, Brillouin spectroscopy studies of relaxor ferroelectrics and metal hydrides, The 14th International Conference on Internal Friction and Mechanical Spectroscopy (Kyoto, Japan, September 5-9, 2005). Ahart, M., R. E. Cohen and R. J. Hemley, High-pressure Raman scattering and x-ray diffraction study of relaxor ferroelectric 0.96Pb(Zn1/3Nb2/3)O3-0.04PbTiO3, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Ahart, M., P. Dera, R. E. Cohen and R. J. Hemley, Pressure-induced phase transitions in PbTiO3, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Ahart, M., P. Dera, R. J. Hemley and R. E. Cohen, Pressure induced phase transitions in PbTiO3, Fundamental Physics of Ferroelectrics 2006 (Williamsburg, VA, February 12-15, 2006). Aihaiti, M., Brillouin scattering studies of hydrides and ferroelectrics, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Asthagiri, A., Z. Wu, N. Choudhury and R. E. Cohen, Molecular dynamics simulations of PMN and PT, Fundamental Physics of Ferroelectrics 2005 (Williamsburg, VA, February 6-9, 2005). Asthagiri, A., Z. Wu, N. Choudhury and R. E. Cohen, Multi-scale modeling of relaxor ferroelectrics, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Banighan, E. J., R. Caracaz, P. Beck and R. J. Hemley, Theoretical and experimental Raman study of spinel, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Beck, P., A. Goncharov and R. J. Hemley, High-pressure high-temperature Raman spectroscopy of san carlos olivine, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Bommannavar, A., M. Somayazulu, V. Naik and R. Naik, High pressure studies on nanoparticles of gamma Fe2O3, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Caracas, R. and R. E. Cohen, Total energy and linear response computations for perovskite and post-perovskite phases in the MgSiO3-FeSiO3-Al2O3 system, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Caracas, R. and R. E. Cohen, Effects of chemistry on the properties and transformation of perovskite to the post- perovskite phases with impllications for the lowermost mantle, AGU 2005 Joint Assembly (New Orleans, LA, May 23-27, 2005). Caracas, R. and R. E. Cohen, Searching for ferroelectrics with exotic chemistry, Fundamental Physics of Ferroelectrics 2006 (Williamsburg, VA, February 12-15, 2006). Caracas, R. and R. E. Cohen, Computational study of the pressure behavior of post-perovskite phases, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Caracas, R. and R. E. Cohen, Theoretical determination of the Raman spectra of MgSiO3 under pressure, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Caracas, R., O. Degtyareva, E. Gregoryanz, R. E. Cohen and R. J. Hemley, Theoretical and experimental investigation of the metallic phases of sulfur at megabar pressures, Third Meeting of the Study of Matter at Extreme Conditions (SMEC) (Miami, FL, April 17-21, 2005). Caracas, R., O. Degtyareva, E. Gregoryanz, R. E. Cohen and R. J. Hemley, Incommensurately modulated sulfur at megabar pressures: Experimental and computational study section, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Caracas, R. and B. Mysen, Spectroscopy in mineralogy: theory and experiment I, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Caracas, R. and R. M. Wentzcovitch, Lattice instabilities in CaSiO3 perovskite, Fundamental Physics of Ferroelectrics 2005 (Williamsburg, VA, February 6-9, 2005). Caracas, R., M. E. Wysession and W. L. Mao, Perovskite to post-perovskite phase transitions in the Earth's deep interior I, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Caracaz, R., Dynamic mean-field theory study of FeO, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Chellappa, R., High pressure Raman spectroscopy studies on pentaerythritol, neopentylglycol, and LiAlH4, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Chen, X. J., Neutron diffraction studies of FeO up to 25 GPa, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Chen, X. J., High-pressure superconductivity and mechanical properties of nitrides, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Chen, X. J., Superconductivity of NbN under pressure, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005).

90 Chen, X. J., V. V. Struzhkin, Y. Song, M. Ahart, O. Degtyareva, H. P. Liermann, Z. X. Liu, J. A. Xu, H. K. Mao and R. J. Hemley, High-pressure optical studies of the group IVa hydrides, Second Annual SSAAP Symposium (Las Vegas, Nevada, August 23-24, 2005). Chen, X. J., V. V. Struzhkin, Z. Wu, R. E. Cohen, H. K. Mao and R. J. Hemley, High-pressure behaviors of a niobium nitride single crystal (invited), Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Chen, X. J., V. V. Struzhkin, Z. Wu, R. J. Hemley, H. K. Mao, B. Liang, C. Ulrich and H. Q. Lin, Oxygen isotope effect in layered cuprate superconductors, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Chen, X. J., J. A. Xu, Y. Ding, V. V. Struzhkin, H. K. Mao, R. J. Hemley, J. Z. Zhang, J. Qian and Y. Zhao, Neutron diffraction studies of wustite under pressure up to 25 GPa, Second Annual SSAAP Symposium (Las Vegas, Nevada, August 23-24, 2005). Cohen, R. E., Low symmetry ground state in PMN: Random fields vial unit-cell twinning, or multiscale disorder in relaxors, Fundamental Physics of Ferroelectrics 2005 (Williamsburg, VA, February 6-9, 2005). Cohen, R. E., Origin of large response in high electromechanical coupling transducer materials, Fundamental Physics of Ferroelectrics 2006 (Williamsburg, VA, February 12-15, 2006). Cohen, R. E., Computation of thermal, elastic, and magnetic properties at high pressure, Frontiers in High Pressure Research (Kibbutz Ein-Gued, Dead Sea, Israel, March 2-7, 2006). Cohen, R. E., Theory of iron at high pressure and temperature (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Cohen, R. E., Multiscale modeling of magnetism in iron at high pressures, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Cohen, R. E., Quantum Monte Carlo simulations of phase transitions in silica, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Cohen, R. E., N. Choudhury, Z. Wu, A. Asthagiri, M. Ahart and R. J. Hemley, Polarization rotation and domain contributions to large electromechanical coupling in relaxor ferroelectrics (invited), U.S. Navy Workshop on Acoustic Transduction Materials and Devices (State College, PA, May 10-12, 2005). Cohen, R. E. and X. Sha, Thermoelasticity of iron from first-principles (invited), ASC Road Show (Lawrence Livermore National Laboratory, Livermore CA, May 16, 2005). Cohen, R. E. and R. M. Wentzcovitch, Spectroscopy in mineralogy: theory and experiment II, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Cohen, R. E. and Z. Wu, Ferroelectricity in PbTiO2 and BaTiO3, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Crowhurst, J. C., A. F. Goncharov, C. L. Evans, P. G. Morrall, J. L. Ferriera and A. J. Nelson, Synthesis and stoichiometries of noble metal nitrides, Joint 20th AIRAPT - 43rd EHPRG International Conference on High Pressure Science and Technology (Karlsruhe, Germany, June 27-July 1, 2005). Cunningham, N. C., W. Qiu, K. M. Hope and Y. K. Vohra, Structural trends in heavy rare earth metals at high pressure - possible f-delocalization mechanisms, Gordon Conference on Research at High Pressure (Biddeford, ME, June 25-30, 2006). Degtyareva, O., R. Caracas, E. Gregoryanz, R. E. Cohen and R. J. Hemley, Incommensurately modulated sulfur at megabar pressures: experimental and computational study, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Degtyareva, O., R. Caracas, E. Gregoryanz, M. Somayazulu, R. E. Cohen, H. K. Mao and R. J. Hemley, Charge- density wave in the incommensurate phase of metallic sulfur at megabar pressure, IUCr Meeting (Florence, Italy, August, 2005). Degtyareva, O., E. Gregoryanz and R. J. Hemley, Phase diagrams and complex crystal structures of selected elements, Third Meeting of the Study of Matter at Extreme Conditions (SMEC) (Miami, FL, April 17-21, 2005). Delaire, O., T. Swan-Wood, M. Kresch and B. Fultz, Thermodynamics of impurities in vanadium, TMS Annual Meeting (San Antonio, TX, March 12-16, 2006). Demouchy, S., S. J. Mackwell, F. Gillard, S. D. Jacobsen and C. R. Stern, New insights into water storage in the uppermost mantle: evidence of dehydration in peridotites, Geophysical Research Abstracts, European Geosciences Union, 7, 01563 (2005). Dera, P., Oscillation Laue analysis (OLA) - a new crystal structure determination method for mineral physics, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Dlott, D. D., Ultrafast nonlinear spectroscopy of molecular shock compression, Physics Division, Los Alamos National Laboratory (Los Alamos, CA, February, 2005).

91 Dlott, D. D., Shock compression of molecules with picosecond time and 1.5 angsrom spatial resolution (invited), Second International Symposium on Interdisciplinary Shock Wave Research (Sendai, Japan, March, 2005). Dlott, D. D., Nanotechnology energetic material dynamics studied with nanometer spatial resolution and picosecond temporal resolution (invited, plenary talk), Sixth International Symposium on Special Topics in Chemical Propulsion (Santiago, Chile, March, 2005). Dlott, D. D., The new wave in shock waves (invited), Department of Physics, University of Southern California (Los Angeles, CA, April, 2005). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures (invited), Department of Physics, University of Southern California (Los Angeles, CA, April, 2005). Dlott, D. D., Vibrational energy with high time and space resolution (invited), Air Force office of Scientific Research Molecular Dynamics Conference (Monteray, CA, May, 2005). Dlott, D. D., Laser-driven shock waves and molecular spectroscopy (invited), CDAC Summer School (Argonne National Laboratory, Argonne, IL, June 1-3, 2005). Dlott, D. D., Shock compresion spectroscopy with high time and space resolution (invited), American Physical Society Topical Meeting on Shock Compression of Condensed Matter (Baltimore, MD, July, 2005). Dlott, D. D., Insensitive energetic materials (invited), Army Research Office MURI Kick-Off Meeting (California Institute of Technology, Pasadena, CA, July, 2005). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures (invited), Telluride Workshop on Vibrational Dynamics (Telluride, CO, August 2005). Dlott, D. D., Ultrafast nonlinear vibrational spectroscopy of water and water at biological interfaces, 2005 DOE/BES Biomolecular Materials Program Meeting (Warrenton, VA, August, 2005). Dlott, D. D., Impact initiation of energetic materials: a molecular perspective (invited), USC Topical Meeting on Shock Waves (Los Angeles, CA, October, 2005). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures (invited), University of Maryland, Department of Chemistry (Baltimore, MD, October, 2005). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures (invited), University of Pennsylvania, Department of Chemistry (Philadelphia, PA, October, 2005). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures (invited), University of Michigan, Department of Chemistry (Ann Arbor, MI, November, 2005). Dlott, D. D., Fundamental dynamic mechanisms (invited), US Army Program Review of Nanotechnology Energetic Materials Efforts (MURI Review) (Aberdeen, MD, November, 2005). Dlott, D. D., Ultrafast dynamics of nanotechnology energetic materials (invited), Materials Research Society Fall Meeting (Boston, MA, November, 2005). Dlott, D. D., Vibrational energy transfer in reverse micelles (invited), Materials Research Society Fall Meeting (Boston, MA, November, 2005). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures (invited), Michigan State University, Department of Chemistry (East Lansing, MI, November, 2005). Dlott, D. D., Interfaces at high pressure (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Dlott, D. D., Vibrational energy at interfaces: Material transformation dynamics (invited), Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Dlott, D. D., Vibrational spectroscopy with high time and space resolution (invited), Carnegie Institute of Washington, Geophysical Laboratory Department Seminar (Washington, DC, May 8, 2006). Dlott, D. D., Ultrafast IR-Raman measurements of water vibrations, Stockholm Discussion Meeting, Local Structure and Molecular Scale Properties of Liquid Water (Stockholm, Sweeden, June, 2006). Dlott, D. D., Vibrational dynamics with high time and space resolution (invited), Gordon Conference on Liquids, University of New England (Biddeford, ME, July, 2006). Dlott, D. D., Vibrational energy relaxation in condensed phases, Telluride Workshop on Vibrational Dynamics (Telluride, Co, July 2006). Dlott, D. D., Vibrational energy in liquids, Telluride Workshop on Vibrational Dynamics (Telluride, CO, July, 2006). Dlott, D. D., Vibrational energy in water, Telluride Workshop on Vibrational Dynamics (Telluride, Co, July, 2006). Dlott, D. D., Vibrational energy in molecules and molecular nanostructures, Auburn University (Auburn, IL, April, 2006). Dlott, D. D. and W. G. Clark, IED detection by nonlinear coherent vibrational spectroscopy (invited), DARPA Workshop on Standoff Detection of Improvised Explosive Devices (Chantilly, VA, November, 2005).

92 Duffy, T. S., Yield strength to Mbar pressures, COMPRES Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (Argonne, IL, October 21-23, 2005). Duffy, T. S., Compressibility and structural evolution of germanate and silicate post-perovskite phases, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Duffy, T. S., Compressibility and structural evolution of germanate and silicate post-perovskite phases (invited), International Union of Crystallography Meeting (Florence, Italy, August 26, 2005). Duffy, T. S., Post-perovskite phases and structures of the deep mantle (invited), International Workshop on Post-Perovskite Phase Transition (Tokyo, Japan, October 3, 2005). Duffy, T. S., Elastic properties of mantle minerals at high pressures (invited), Geological Society of America Annual Meeting (Salt Lake City, UT, October 17, 2005). Duffy, T. S., Elastic properties of hydrous minerals and implications for seismic studies of the upper mantle (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Duffy, T. S., The post-perovskite phase transition and the Earth's core-mantle boundary region (keynote lecture), European Mineralogy and Petrology Meeting (Bristol, UK, September 12, 2006). Duffy, T. S., The post-perovskite phase transition and Earth's core-mantle boundary region (invited), Symposiums on Impacts and Deep Earth Geophysics (Pasadena, CA, May 12, 2006). Duffy, T. S., Recent advances in deep Earth studies (invited), Department of Geophysical Sciences, University of Chicago (Chicago, IL, February 24, 2006). Duffy, T. S. and Z. Mao, Elasticity of the olivine (Mg,Fe)2SiO4 polymorphs: Current understanding and implications for mantle composition, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Emmons, E., Dynamic studies of phase transitions in f-electron materials using photoluminescence spectroscopy, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Evans, W. J., High pressure beryllium: Static and elastic properties, Joint 20th AIRAPT - 43rd EHPRG International Conference on High Pressure Science and Technology (Karlsruhe, Germany, June 27-July 1, 2005). Fei, Y., Challenges in studying the chemistry of deep interior of the Earth (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Fei, Y., NaCl and neon as pressure standards and media, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Feng, Y., R. Jaramillo, T. F. Rosenbaum, O. G. Shpyrko, E. D. Isaacs, G. Srajer, J. Lang, Z. Islam, M. Somayazulu, H. K. Mao and V. Prakapenka, Evolution of Cr's charge and spin density waves under GPa pressures, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Fultz, B., Neutron scattering and the entropy of materials (invited), UCLA Materials Science and Engineering Department Seminar (Los Angeles, CA, January 28, 2005). Fultz, B., The DANSE project (invited), Neutron Science Software Initiative Workshop NeSSI-3 (Santa Fe, NM, April 29, 2005). Fultz, B., Neutron scattering and the entropy of materials (invited), University of New Orleans Chemistry Departmetn Colloquium (New Orleans, LA, May 6, 2005). Fultz, B., Entropy of solid-solid phase transformations: Contributions from vibrational dynamics (invited), Solid-State Phase Transformations in Inorganic Materials 2005 (Phoenix, AX, June 2, 2005). Fultz, B., Phonon thermodynamics in materials under extreme conditions (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Fultz, B., Mössbauer diffractometry (invited), Fourth Nassau Mössbauer Symposium (Garden City, NY, January 14, 2006). Fultz, B., Dynamic data-driven data applications systems for the domain of neutron scattering research (invited), Workshop at the National Science Foundation Headquarters (Washington, DC, January 19, 2006). Fultz, B., Inelastic neutron scattering and entropy (invited), Indiana University Department of Physics Colloquium (Bloomington, IN, May 30, 2006). Fultz, B., Nanostructured materials for lithium and hydrogen storage (invited - Keynote talk), MIT Energy Nanotechnology International Conference (Cambridge, MA, June 27, 2006). Goncharov, A., Optical spectroscopy under extreme conditions (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Goncharov, A., High pressure calibration at high temperatures in the diamond anvil cell using cubic boron nitride, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Goncharov, A. and J. C. Crowhurst, Raman spectroscopy of hot compressed hydrogen and nitrogen - implications for the intramolecular potential, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006).

93 Goncharov, A., H. Kanda and S. Shistov, Pressure dependence of the first-order Raman frequency in isotopically mixed diamond, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Goncharov, A. F., Calibration of pressure sensors for high pressures and temperatures, Third Meeting of the Study of Matter at Extreme Conditions (SMEC) (Miami, FL, April 17-21, 2005). Goncharov, A. F., Polymerization of materials with hydrogen bonds under extreme conditions of high pressure and temperature, Sector 16 APS Review Meeting (Argonne National Laboratory, Argonne, IL, March 3, 2005). Goncharov, A. F., Optical, vibrational, and mechanical properties of materials under extreme conditions II, Carnegie Institution of Washington Colloquium (Geophysical Laboratory, Washington DC, January 5, 2005). Goncharov, A. F., J. C. Crowhurst, J. K. Dewhurst and A. Sharma, Cubic boron nitride under high pressures and temperatures, Joint 20th AIRAPT - 43rd EHPRG International Conference on High Pressure Science and Technology (Karlsruhe, Germany, June 27-July 1, 2005). Goncharov, A. F., J. C. Crowhurst, J. M. Zaug, N. Goldman, L. Fried, C. Mundy and I. F. W. Kuo, Superionic water under extreme conditions of high pressure and temperature, Joint 20th AIRAPT - 43rd EHPRG International Conference on High Pressure Science and Technology (Karlsruhe, Germany, June 27-July 1, 2005). Graham, R. and B. Militzer, Path integral simulations of hydrogen melting at high pressures, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Gramsch, S. A., Overview of CDAC, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Gregoryanz, E., The melting curves of simple solids, Third Meeting of the Study of Matter at Extreme Conditions (SMEC) (Miami, FL, April 17-21, 2005). Gregoryanz, E., C. Sanloup, M. Somayazulu and R. J. Hemley, X-ray diffraction and the structures of nitrogen at megabar pressures, Third Meeting of the Study of Matter at Extreme Conditions (SMEC) (Miami, FL, April 17-21, 2005). Haugen, B., Conduction in the lower mantle: Optical absorption spectra of iron-bearing magnesium silicate perovskite at lower mantle pressures, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Heinz, D., Experimental studies of core minerals at core conditions (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Heinz, D. L., W. L. Mao, A. J. Campbell and G. Shen, Phase realtions of Fe-Ni alloys at high pressure and temperature, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Hemley, R. J., Synchrotron studies of matrials at extreme conditions (invited), (Orlando, FL, 2005). Hemley, R. J., New materials chemistry under pressure (invited), Howard University Department of Chemistry (Washington, DC, February 11, 2005). Hemley, R. J., Synchrotron radiation and high pressure: New light on materials under extreme conditions (invited), Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Hemley, R. J., Materials under pressure: new findings and phenomena (invited), Finish Physical Society (Helsinki, Finland, March 16, 2005). Hemley, R. J., New visions of matter with diamonds and light (invited), Carnegie Evening 2005, Carnegie Institution of Washington (Washington, DC, May 5, 2005). Hemley, R. J., Compressing materials from simple to complex: New findings and phenomena (invited), Joint 20th AIRAPT - 43rd EHPRG International Conference on High Pressure Science and Technology (Karlsruhe, Germany, June 27-July 1, 2005). Hemley, R. J., New developments at CDAC - The Carnegie/DOE Alliance Center: A center of excellence in high pressure science and technology (invited), Stewardship Science Academic Alliances Program Symposium (Las Vegas, NV, August 23-24, 2005). Hemley, R. J., Diamond windows on new chemistry (invited), Wesleyan University (Middletown, CT, September 30, 2005). Hemley, R. J., New findings in materials under pressure (invited), Massachusetts Institute of Technology (Cambridge, MA, February 6, 2006). Hemley, R. J., Overview of new developments and future prospects in high-pressure research (invited), Frontiers in High Pressure Research (Kibbutz Ein-Gued, Dead Sea, Israel, March 2-7, 2006). Hemley, R. J., New findings in materials under pressure (invited), Dalhousie University (Halifax, Nova Scotia, Canada, March 23, 2006). Hemley, R. J., Emerging diamond technology and the science of extreme conditions (invited), ICOPS (Traverse City, Michigan, June 4-8, 2006). Hemley, R. J., Current problems in high-pressure science (invited), Workshop on Synergy of 21st Century High- Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006).

94 Hemley, R. J., New findings in molecular systems unde pressure (invited), ACS National Meeting (San Francisco, CA, September 10-14, 2006). Hemley, R. J., New findings in materials under pressure (invited), University of Virginia, Chemistry Department (Charlottesville, VA, October 20, 2006). Hemley, R. J., New findings in materials under pressure (invited), 53rd Midwest Solid State Conference (Kansas City, Missouri, October 6-8, 2006). Hemley, R. J., New findings in materials under pressure (invited), Fall 2006 Joint Meeting of the Texas sections of the American Physical Society, American Association of Physics Teachers, Zone-13 of the Society of Physics Students, Forum on Industrial and Applied Physics, National Society of Hispanic Physicists, and National Society of Black Physicists (Arlington, TX, October 5-7, 2006). Hemley, R. J., New studies of low-Z systems under pressure, Sixth International Conference on Cryocrystals and Quantum Crystals (Kharkov, Ukraine, September 3-7, 2006). Hemley, R. J., Planetary fluids under extreme conditions, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Hemley, R. J., J. F. Lin, E. Gregoryanz, A. F. Goncharov, V. V. Struzhkin, M. Somayazulu, H. K. Mao and Y. Yoshimura, H2O under extreme conditions, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Hemley, R. J., C. S. Yan and S. S. Ho, Prospects of large single crystal CVD diamond, 1st International Industrial Diamond Conference (Barcelona, Spain, October 20-21, 2005). Hemley, R. J., C. S. Yan, S. S. Ho, H. Shu and H. K. Mao, New diamond technology for geoscience and beyond, SLC 2005, GSA Annual Meeting (Salt Lake City, UT, October 16-19, 2005). Hemley, R. J., C. S. Yan and H. K. Mao, The new diamond age - from Earth to CVD (invited), 2006 DeBeers Diamond Conference (Cambridge, England, July 10-12, 2006). Jackson, J. M., Physical properties of minerals and melts under high-pressure (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Jackson, J. M., The electronic structure of iron in aluminous (Mg, Fe)SiO3 perovskite at high-pressures and temperatures, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Jackson, J. M., Y. Fei, M. Hu and H. K. Mao, Sound velocities of upper mantle minerals determined by nuclear resonant inelastic x-ray scattering, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Jacobsen, S. D., Identifying hydration in Earth's interior (invited), 21st Century Center of Excellence Program, Tohoku University (Sendai, Japan, July 22, 2005). Jacobsen, S. D., High-pressure crystal chemistry and hydrogen storage in the Earth's mantle (invited), Northwestern University, Department of Geological Science (Evanston, IL, April 15, 2005). Jacobsen, S. D., High-pressure crystal chemistry and hydrogen storage in the Earth's mantle (invited), Princeton University, Department of Geosciences (Princeton, NJ, April 7, 2005). Jacobsen, S. D., High-pressure synchrotron-IR studies of OH in MgSiO3 polymorphs in Earth's mantle, COMPRES Workshop: Synchrotron Infrared Spectroscopy for High Pressure Geoscience and Planetary Science (Brookhaven National Laboratory, November 4, 2005). Jacobsen, S. D., Bridging experimental and observational geophysics for identifying hydration in the Earth's interior, Bayerisches Geoinstitut (Bayreuth, Germany, October 17, 2005). Jacobsen, S. D., Identifying hydration in the Earth's interior, Tohoku University, Graduate School of Science (Sendai, Japan, July 22, 2005). Jacobsen, S. D., Identifying hydration in the mantle transition zone: Emerging constraints from mineral physics and seismology (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Jacobsen, S. D., Seismic structure of a hydrous mantle transition zone: the emerging picture from mineral physics, Yale University, Department of Geology and Geophysics (New Haven, CT, January 20, 2006). Jacobsen, S. D., Seismic structure of a hydrous mantle transition zone: the emerging picture from mineral physics, Northwestern University, Department of Geological Sciences (Evanston, IL, February 13, 2006). Jacobsen, S. D., Seismic structure of a hydrous mantle transition zone: the emerging picture from mineral physics, Virginia Polytechnic Institute and State University, Department of Geological Sciences (Blacksburg, VA, February 23, 2006). Jacobsen, S. D., Seismic structure of a hydrous mantle transition zone: the emerging picture from mineral physics, University of Minnesota, Department of Geology and Geophysics (Minneapolis, MN, March 2, 2006). Jacobsen, S. D., Seismic structure of a hydrous mantle transition zone: the emerging picture from mineral physics, University of Illinois Chicago, Department of Earth and Environmental Science (Chicago, IL, September 7, 2006). Jacobsen, S. D., Effect of water on the equation of state of nominally anhydrous minerals, Mineralogical Society of America Short Course: Water in Nominally Anhydrous Minerals (Verbania, Italy, October 1-4, 2006).

95 Jacobsen, S. D., Sound volocities of hydrous olivine and the effects of water on the equation of state of nominally anhydrous minerals, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Jacobsen, S. D., Z. Liu, J. F. Lin, E. F. Littlefield, S. Demouchy, G. Shen, V. B. Prakapenka, F. Langenhorst and R. J. Hemley, High-pressure synchrotron-IR studies of hydrous transition zone and lower-mantle minerals in the laser-heated diamond cell, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Jacobsen, S. D., H. J. Reichmann, A. Kantor, H. Spetzler, J. R. Smyth, C. M. Holl, H. K. Mao and R. J. Hemley, Elastic properties of dense oxide minerals and other applications of GHz-ultrasonic interferometry, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Jacobsen, S. D., J. R. Smyth and S. van der Lee, Identifying hydration in Earth's mantle (invited), 21st COE International Symposium on Spatial and Temporal Fluctuations in the Solid Earth (Sendai, Japan, July, 2005). Jacobsen, S. D., J. R. Smyth and S. van der Lee, Effect of water on the elastic properties of nominally anydrous minerals (invited), Eos Trans. AGU Jt. Assem. Suppl., Abstract., 87 (2006). Jenkins, T., Spallation Neutrons and Pressure (SNAP): A state of the art high pressure diffractomenter, 230th ACS National Meeting (Washington, DC, August 28-September 1, 2005). Jenkins, T., Hydrogen clathrate compounds for hydrogen storage by neutron and visible spectroscopy methods, 230th ACS National Meeting (Washington, DC, August 28-September 1, 2005). Jenkins, T., R. J. Hemley, H. K. Mao, W. Mao, V. V. Struzhkin, B. Militzer and J. Leao, Examination of hydrogen clathrates vibrational spectra by inelastic neutron scattering American Conference on Neutron Scattering (St. Charles, IL, June 18-22, 2006). Johnson, K., J. Feldman and R. J. Hemley, Vibron dynamics of hydrogen at high pressures and temperatures, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Kalita, P. E., C. L. Gobin, R. J. Hemley and K. Lipinska-Kalita, High pressure-induced phase transition in - Ga2O3: in situ synchrotron x-ray diffraction studies up to 70 GPa, Stewardship Science Academic Alliances Program Symposium (Las Vegas, NV, August 23-24, 2005). Kalita, P. E., R. Kumar and A. Cornelius, Ambient and high pressure structural studies on TiH2, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Kalita, P. E., G. Mariotto, Y. Ohki and K. E. Lipinska-Kalita, Core/shell nanocrystalline clusters in a glass matrix: a high pressure synchrotron x-ray diffraction study, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Kantor, A., I. Y. Kantor, L. S. Dubrovinsky and S. D. Jacobsen, New experimental setup for high-pressure high- temperature gigahertz ultrasonic interferometry, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Lazicki, A., A new high-pressure phase of Li3N: Stability of the N3 Ion to 200 GPa, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Lee, K., Pressure and chemistry-dependent electron capture radioactive decay, New Mexico Institute of Mining and Technology (Sorocco, NM, March 30, 2006). Lee, K., Pressure and chemistry-dependent electron capture radioactive decay, Ludwig Maximilians University (Munich, Germany, June 30, 2006). Lee, K., Pressure and chemistry-dependent electron capture radioactive decay, Bayerisches Geoinstitut (Beyreuth, Germany, July 6, 2006). Lee, K. K. M., Pressure- and chemistry-dependent electron-capture radioactive decay of 7Be, 22Na and 40K in crystalline materials, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Lee, K. K. M., Is potassium really in the core? Ab-initio predictions of potassium partitioning between (Mg,Fe)SiO3 perovskite and iron, (2006). Lee, S. K., Y. Fei, G. Cody, B. Mysen, H. K. Mao and P. Eng, Atomistic and nanoscale origins of macroscopic properties of silicate melts at high-pressure: Spectroscopy and quantum chemical calculations, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Li, B., J. Kung, W. Liu, W. L. Mao, H. K. Mao, T. Uchida and Y. Wang, In-situ sound velocity measurements on bcc and hcp phases of Fe, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Liermann, H. P., Current and future experimental techniques at beamline 16 BM, High Pressure Collaboration Access Team: Simultaneous high-pressure, -temperature powder and single crystal x-ray diffraction, combined with in situ fluorescence and Raman spectroscopy, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Liermann, H. P., White beam Laue studies at beamline 16 BM-B, High Pressure Collaboration Access Team, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Lin, H. Q., X. J. Chen, V. V. Struzhkin, Z. G. Wu, R. J. Hemley, H. K. Mao, B. Liang, C. Ulrich and C. T. Lin, Theoretical and experimental studies on the oxygen isotope effect in cuprate superconductors, The 8th International Conference on Materials and Mechanisms of Superconductivity and High Temperature Superconductors (Dresden, Germany, July, 2006).

96 Lin, J. F., V. V. Struzhkin, S. D. Jacobsen, W. Sturhahn, A. G. Gavriliuk, J. M. Jackson, M. Hu, P. Chow, J. Kung, H. Liu, G. Shen, V. B. Prakapenka, J. Zhao, H. K. Mao, C. Yoo and R. J. Hemley, Effects of the spin transition of iron in magnesiowustite, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Lipinska-Kalita, K., S. Gramsch, P. Kalita and R. J. Hemley, Raman scattering studies of high-pressure stability and transformations in the matrix of a nanostructured glass-ceramic composite, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Lipinska-Kalita, K., P. Kalita and R. J. Hemley, Synchrotron x-ray diffraction probe of pressure-induced phase transition in the nanocrystalline phase of a glass-based composite, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Lipinska-Kalita, K. E., High pressure-induced phase transition in a nanostructured composite: In situ synchrotron x-ray diffraction investigations, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Lipinska-Kalita, K. E., High pressure-induced phase transition -GA2O3: In situ synchrotron x-ray diffraction studies up to 70 GPa, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Lipinska-Kalita, K. E., P. E. Kalita and R. J. Hemley, High pressure-induced phase transition in a nanostructured composite: In situ synchrotron x-ray diffraction investigations, Stewardship Science Academic Alliances Program Symposium (Las Vegas, NV, August 23-24, 2005). Lipinska-Kalita, K. E., P. E. Kalita, R. J. Hemley and C. L. Gobin, High pressure-induced phase transition in - Ga2O3: in situ synchrotron x-ray diffraction studies up to 70 GPa, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Lipinska-Kalita, K. E., D. M. Krol, R. J. Hemley, G. Mariotto, P. E. Kalita and Y. Ohki, Temperature effects on luminescence properties of Cr3+ ions in heterophase oxide glass based nanostructured media, 17th University Conference on Glass Science and 1st International Materials Institute Workshop on NEW FUNCTIONALITY IN GLASSES (State College, PA, June 26-30, 2005). Lipinska-Kalita, K. E., M. Pravia and M. Nichol, Angle-dispersive high-pressure synchrotron radiation x-ray diffraction studeis of pentaerythritol tetranitrate on compression sequence up to 30 GPa, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Littlefield, E. F., S. D. Jacobsen, Z. Liu and R. J. Hemley, Effects of water on the behavior of MgSiO3- clinoenstatie at high pressure, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Liu, H., Future development for DAC radial diffraction studies, COMPRES Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (Argonne, IL, October 21-23, 2005). Liu, H., J. Chen, J. Hu, C. Martin, D. J. Weidner, D. Hausermann and H. K. Mao, Structural refinement for NaMgF3 perovskite under high pressure, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Liu, Z., A high-pressure microspectroscopy beamline at the NSLS, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Ma, Y., High pressure research at Texas Tech University (plenary presentation), Chinese High Pressure Conference (Jilin, China, August 1, 2006). Ma, Y., Application of synchrotron x-ray in high pressure (invited), Southwest Jiatong University (Chengdu, China, July 23, 2006). Majzlan, J., S. Speziale and T. S. Duffy, Measurement of elastic properties of alunite by Brillouin spectroscopy, European Geosciences Union Meeting (Vienna, Austria, 2005). Mao, H. K., Synchrotron x-ray and magnetic susceptibility probes in diamond anvil cells, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Mao, H. K., Radial x-ray diffraction in diamond anvil cell, COMPRES Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (Argonne, IL, October 21-23, 2005). Mao, H. K., Synergy of high-pressure research (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Mao, H. K., The mineral physics exploration of the Earth's deep interior (invited), Geophysical Laboratory Centennial Celebration (Carnegie Institution of Washington, Washington DC, May 3, 2006). Mao, H. K., High pressure - A new dimention in physics, chemistry, materials science, geoscience, and biology (invited), Forum on Science Frontier and China's Opportunities in the 21st Century (Beijing, China, May 24-26, 2006). Mao, H. K., High-pressure synergetic consortium - A new approach to high-pressure research at national facilities (invited), Future Frontiers in High-Pressure Science with ERL X-Ray Beams Workshop (Cornell University, Ithaca, NY, June 5-6, 2006). Mao, H. K., High-pressure - A new dimention in physics, chemistry, materials science, geoscience, and biology (plenary talk), Academia Sinica's Biannual Meeting (Taipei, Taiwan, July 1-5, 2006). Mao, H. K., New diamond science and technology for the 21st century (invited), Taipei International Meeting Center (Taipei, Taiwan, July 7, 2006).

97 Mao, H. K., The formation of elasticity, rheology, and dynamics of iron-rich silicate in core-mantle boundary layer (keynote talk), 19th General Meeting of the International Mineralogical Association (Kobe, Japan, July 23-28, 2006). Mao, H. K., Core-mantle interaction - The formation, elasticity, rheology, and dynamics of iron-rich silicate in core-mantle boundary layer (invited), Fifth International Conference on Synchrotron Radiation in Materials Science (SRMS-5) (Chicago, IL, July 31, 2006). Mao, H. K. and W. L. Mao, Integrated in-situ probes for structural and dynamic properties of geological materials at ultrahigh pressures and temperatures, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Mao, W. L., Experimental determination of elasticity of iron at high pressure, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Mao, W. L., Elasticity of iron-rich silicate in Earth's D" layer, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Mao, W. L., H. K. Mao, M. Hu, P. Chow, Y. Meng, G. Shen, V. B. Prakapenka, J. Shu, A. J. Campbell, Y. Fei, D. L. Heinz and R. J. Hemley, Physics and chemistry of ferromagnesian silicate post perovskite, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Mao, Z., Single-crystal elasticity of hydrous wadsleyite in Brillouin scattering, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Mao, Z., F. Jiang and T. S. Duffy, Single-crystal elasticity of zoistite Ca2Al3Si3O12(OH) by Brillouin scattering, COMPRES Annual Meeting (Mohonk, NY, June, 2005). Mao, Z., F. Jiang and T. S. Duffy, Single-crystal elasticity of zoisite Ca2Al3O12(OH) by Brillouin scattering, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Meng, Y., HPCAT ID beamline overview, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Meng, Y., The power of an integrated approach in high-pressure research, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Meng, Y., Advances in high-pressure x-ray spectroscopy, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Meng, Y., Current status and future plan for radial XRD with in-situ laser heating, COMPRES Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (Argonne, IL, October 21- 23, 2005). Merkel, S., Radial diffraction in the DAC: Practical and theoretical considerations, COMPRES Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (Argonne, IL, October 21- 23, 2005). Merkel, S., A. Kubo, S. Speziale, L. Miyagi, H. R. Wenk, T. S. Duffy and H. K. Mao, Plastic deformation of MgGeO3 post-perovskite beyond 100 GPa, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Merkel, S., L. Miyagi, S. Speziale, H. R. Wenk, A. Kubo, T. S. Duffy and H. K. Mao, Texture development in MgGeO3 postperovskite, Eos Tran. AGU Fal Meet., Suppl., submitted (2005). Miao, S., M. Kocher, B. Fultz, P. Rez, Y. Ozawa, R. Yazami and C. C. Ahn, Local electronic structure of layered LixNi0.33Mn0.33Co0.33O2, Electrochemical Society Fall Meeting (Los Angeles, CA, October 18, 2005). Militzer, B., Exchange frequencies in helium-4 crystals with defects, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Militzer, B., Path integral simulations of hydrogen-helium mixtures in planet interiors (invited), SMEC (Maimi, FL, April, 2005). Militzer, B., Shock hugoniot calculations of dense liquid helium, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Militzer, B., Modeling Jupiter's interior with a hydrogen-helium equation of state derived from first principles computer simulations, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Miyagi, L., Berkeley CDAC collaborations in texture analysis of Earth materials at high pressures, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Miyagi, L., Deformation of the CaIrO3 post-perovskite phase to 5 GPa and 1300 K in the multi-anvil press, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Montgomery, W. and R. Jeanloz, Life on extrasolar planets: The persistance and stability of cyanuric acid in protoplanetary conditions, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Okuchi, T., M. Takigawa, J. Shu, H. K. Mao, R. J. Hemley and T. Yagi, Structure and transport properties of hydrogen filled ices (H2O:1/6H2 and H2O:H2) at pressures to 4 GPa by solid state diamond-anvil-cell NMR, Eos Trans. AGU Fall Meet., Suppl., 86 (2005). Pravia, M., K. Lipinska-Kalita, H. Giefers, Y. R. Shen, M. Nichol, M. Somayazulu and M. Hu, High pressure studies of PETN up to 74 GPa, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21- 25, 2005).

98 Qiu, W., Calibration of an isotopically enriched carbon-13 layer pressure sensor to 156 GPA in a diamond anvil cell, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Reid, F. R., Synthesis and high-pressure synchrotron-infrared studies of OH-bearing silicate perovskite in the laser-heated diamond cell, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Runge, C., A. Kubo, B. Kiefer, T. Uchida, Y. Wang, N. Nishiyama and T. S. Duffy, New techniques for melting curve determination at high pressures: Application to silicon, COMPRES Annual Meeting (Mohonk, NY, June, 2005). Runge, C. E., A. Kubo, B. Kiefer, T. S. Duffy, V. Prakapenka, G. Shen and Y. Meng, Equation of state of MgGeO3 perovskite to 65 GPa: Comparison with the post-perovskite phase, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Sha, X. and R. E. Cohen, Thermal equation of state of bcc and hep Fe: linear response quasi-harmonic lattice dynamics, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Sha, X. and R. E. Cohen, First principles phonon and elasticity computations iron under extreme conditions, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Sha, X. and R. E. Cohen, First-principles study on hcp Fe under Earth's core conditions, Eos Trans. AGU Jt. Assem. Suppl., Abstract, 87 (2006). Shen, G., Experimental studies of phase diagram of iron (invited), Workshop on Synergy of 21st Century High- Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Song, Y., Pressure-induced transitions in silane, Second Annual SSAAP Symposium (Las Vegas, NV, August 23- 24, 2005). Struzhkin, V. V., Applications of NRIXS and NFS techniques at high pressures (invited), Workshop on Nuclear Resonant Scattering on Earth Materials using Synchrotron Radiation (Argonne National Laboratory, Argonne, IL, February 12-13, 2005). Struzhkin, V. V., X-ray emission spectroscopy, Frontiers in High Pressure Research (Kibbutz Ein-Gued, Dead Sea, Israel, March 2-7, 2006). Struzhkin, V. V., Magnetism and superconductivity at high pressures (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Struzhkin, V. V., Optimizing hydrogen clathrates for hydrogen storage, Sixth International Conference on Cryocrystals and Quantum Crystals (Kharkov, Ukraine, September 3-7, 2006). Struzhkin, V. V., X. J. Chen, O. Degtyareva, M. Ahart, Y. Song, H. P. Liermann, J. Xu, H. K. Mao and R. J. Hemley, Optical studies of compressed silane up to 40 GPa, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Tamblyn, I., J. Vorberger, B. Militzer and S. A. Bonev, Simulations of dense hydrogen and hydrogen-helium mixtures at conditions relevant to gas planet interiors, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Tibrewala, J., Z. Liu and L. M. Miller, Pressure-induced structural changes in bone mineral and model compounds, NSLS Lunch Seminar, 2005). Velisavljevic, N., Simultaneous electrical and x-ray diffraction studies on f-electron metals at high pressures using designer diamond anvils, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Vohra, Y., Grand challenges in f-electron metals research at high pressures and low temperatures using designer anvil cells (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Vohra, Y., Basic science and applications of vapor grown diamods of high pressure research (invited), Gordon Conference on Research at High Pressure (Biddeford, ME, June 25-30, 2006). Vorberger, J., I. Tamblyn, S. A. Bonev and B. Militzer, Hydrogen-helium mixtures under giant gas planet conditions, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Vorberger, J., I. Tamblyn, S. A. Bonev and B. Militzer, Equation of state calculations for hydrogen and helium under giant planet conditions, Dalhousie 87 (2006). Wan, J. T. K., R. Car, S. Scandolo and T. S. Duffy, First principles study of liquid MgSiO3 at conditions of the Earth's deep mantle, American Physical Society March Meeting (Los Angeles, CA, March, 2005). Wenk, H. R., Texture information from radial DAC experiments and relevance for deep earth geophysics, illustrated with examples, COMPRES Workshop on Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures (Argonne, IL, October 21-23, 2005). Wenk, H. R., Deformation experiments at ultrahigh pressure: Where we are and where we should be going (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Wenk, H. R., Preferred orientation and anistropy in shales, Eos Trans. AGU Fall Meet., Suppl., 87 (2006).

99 Wu, Z., A. Asthagiri, N. Choudhury, W. Zhigang and R. E. Cohen, Multi-scale modeling of relaxor ferroelectrics, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Wu, Z. and R. E. Cohen, Pressure-induced anomalous enhancement of piezoelectricity and polerization rotation via an unexpected monoclinic phase of PbTiO3, Bull. Am. Phys. Soc. (APS March Meeting) (Los Angeles, CA, March 21-25, 2005). Wu, Z. and R. E. Cohen, Origin of large response in high electromechanical coupling transducer materials, Fundamental Physics of Ferroelectrics 2006 (Williamsburg, VA, February 12-15, 2006). Wu, Z. and R. E. Cohen, A more accurate generalized gradient approximation for solids, Bull. Am. Phys. Soc. (APS March Meeting) (Baltimore, MD, March 13-17, 2006). Xu, J., Progress on moissanite anvil cells in neutron diffraction studies (invited), The 2nd SNAP Symposium (Spallation Neutron Source, Oak Ridge National Laboratory, Oakridge, TN, July 17-20, 2005). Xu, J., Application of high-pressure research - in Biosciences (invited), The 15th Annual Conference on Life and Food Sciences (Harbin Institute of Technology, Harbin, China, August 15, 2005). Xu, J., Progress on moissanite anvil cells in neutron diffraction studies (invited), High-Pressure Science and Technology - 2005 (Beijing Synchrotron Research Facility, Institute of High Pressure Physics, Chinese Academy of Sciences, Beijing, China, September 6, 2005). Xu, J., Variablity in the vertical structure of the indonesian thoroughflow during the last 140 kyr: evidence from the timor outflow, Eos Trans. AGU Fall Meet., Suppl., 87 (2006). Yan, C. S., New developments in fabrication of large single crystal diamond by chemical vapor deposition, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005). Yan, C. S., Y. C. Chen, S. S. Ho, H. K. Mao and R. J. Hemley, Large single crystal CVD diamonds at rapid growth rates, 8th Applied Diamond Conference, NanoCarbon 2005 (Argonne National Laboratory, Argonne, Illinois, May 15-19, 2005). Yan, C. S., Y. C. Chen, S. S. Ho, H. K. Mao and R. J. Hemley, Large single crystal CVD diamonds at rapid growth rates, The 10th International Conference on New Diamond Science and Technology (AIST, Tsukuba, Japan, May 11-14, 2005). Yan, C. S., Y. C. Chen, S. S. Ho, H. K. Mao, R. J. Hemley, M. Origlieri, S. Krasnicki and Y. Tzeng, Characterization of single-crystal diamonds grown by high growth rate chemical vapor deposition, 8th Applied Diamond Conference, NanoCarbon 2005 (Argonne National Laboratory, Argonne, Illinois, May 15-19, 2005). Yan, C. S., S. S. Ho, J. Lai, S. Krasnicki, H. K. Mao and R. J. Hemley, Development of the microwave plasma CVD technique for rapid growth of large single-crystal diamond, 2006 IEEE International Conference on Plasma Science (Traverse City, MI, June 4-8, 2006). Yarger, J., Structural transformations in liquids and glasses under extreme conditions (invited), Workshop on Synergy of 21st Century High-Pressure Science and Technology (Argonne, IL, April 29-May 1, 2006). Yarger, J., High-pressure and spin enhanced neutron scattering (invited), Argonne National Laboratory, Intense Pulsed Neutron Source (Argonne, IL, April, 2006). Yarger, J., High-pressure quenched glasses (invited), Arizona State University, Chemistry & Biochemistry Symposium (Tempe, AZ, October, 2006). Yoshimura, Y., H. K. Mao and R. J. Hemley, In situ Raman spectroscopy study on the reversible transition between low-density and high-density amorphous ices at 135 K, 3rd Asian Conference on High Pressure Research (China, October 16-20, 2006). Zhao, Y., High preessure neutron diffraction at LANSCE, Second Annual SSAAP Symposium (Las Vegas, NV, August 23-24, 2005).

100 APPENDIX II: CDAC Synchrotron Users/Experiments (APS and NSLS) for Year 3 A. HPCAT (APS) A large part of our annual budget was dedicated to the completion of construction and commissioning of the HPCAT facility. In addition to the 30% membership obtained by CDAC in HPCAT, the support generated by SSAAP funding made possible significant scientific productivity of this state-of-the-art high-pressure facility. Asterisks denote work done with beam time available through CDAC.

User Name Affiliations Project Dates M. Lucas California Institute of 16-ID-D NFS July 23-25, A. Papandrew Technology Raman spectroscopy 2005 J. F. Lin LLNL Raman spectroscopy July 25, 2005 I. S. Lynbutin ICRAS FeD – magnetic crystals July 26-August 2, 2005 V. Struzhkin Carnegie Raman spectroscopy July 27-29, 2005 G. Amulele University of Hawaii EOS: Olivine, SiC, boron carbide July 28-31, S. Mariappan Raman spectroscopy 2005 A. Goncharov Carnegie XRD: Water August 1-5, Laser Heating 2005 P. Liermann Carnegie Raman spectroscopy August 5-7, 2005 S. Merkel University of Radial diffraction: Silicate post perovskite August 5-7, A. Kubo California – Berkeley 2005 L. Miyagi S. Merkel University of Raman spectroscopy August 6-8, California – Berkeley 2006 T. Duffy Princeton J. Mitchell ANL-MSD Manganate perovskites: XRD August 9-10. J. Hill 2005 Olga Degtyareva Carnegie XRD,Na,S,AS August 9-12, B. Maddox 2005 Raman spectroscopy J. Shu Carnegie XRD August 10-15, 2005 J. F. Lin LLNL Raman spectroscopy August 13, 2005 J. Santillan MIT XRD August 12-15, S. Landin 2005 D. Shim A. Lazicki LLNL XRD and laser heating Be August 16-18, W. Evans 2005 H. Cynn Z. Jenei Jennifer Jackson ANL (Mg,Fe)SiO3 perovskite: XRD August 18, 2005 J. Lang ANL Neutron x-ray summer school experiments August 20, 2005

101 B. Olsen University of Neutron School August 19-20, California – Berkeley 2005 G. Sauteiede University of Delaware N. Suwarromaml NOIT M. Kim University of Mexico T. Ziemann University of Notre L. Debeer-Schmitt Dame N. Cunningham University of Alabama – Birmingham G. Lau Princeton P. Filson West Virginia University J. Koo State University of New York, Stony Brook A, Cemils University of Nevada Heavy fermion materials: XRD August 22-25, H. Brooks – Las Vegas 2005 R. Kumar C. Pareda E. Sokol J. Orwig M. Jacobsen A. Bennett J. McClure M. Pravica University of Nevada XRD August 23-25, – Las Vegas X-ray Raman spectroscopy 2005 H. P. Lierman Carnegie Commissioning and testing of single crystal October 3, 2005 G. Shen and powder x-ray diffraction techniques on 16BM-B J. Shu Carnegie Silicate post-perovskite: XRD October 11-14, 2005 H. Liu HPCAT Raman spectroscopy October 12, 2005 J. F. Lin LLNL X-ray Raman spectroscopy October 13, 2005 V. Iota LLNL XRD - Iodine 12 and Gallium Phosphide October 14-17, H. Cynn 2005 J. Liu Z. Jenei H. Giefers University of Nevada XRD October 20-22, – Las Vegas 2005 C. Gobin University of Nevada XRD October 20-21, – Las Vegas 2005 C. D. Martin State University of Perovskite ot post-perovskite transition in October 23-24, New York, Stony NaMgF3: XRD 2005 Brook Tanja Cuk Stanford University Cuprate superconductors: XRD October 26, 2005 V. Struzhkin Carnegie XRD October 26, A. Goncharov 2005 P. Liermann HPCAT Commissioning of BM-D October 26, G. Shen 2005 J. Crowhurst LLNL Noble metal nitrides: XRD October 27, 2005

102 R. Kumar University of Nevada XRD October 28, Patricia Kalita – Las Vegas 2005 M. Jaconsen C. Jensen D. Antonion M. Pravica University of Nevada X-ray Raman spectroscopy October 28-30, A. Bennett – Las Vegas 2005 J. McClure J. Feng LLNL X-ray Raman spectroscopy October 28- C. S. Yoo November 11, 2005 J. F. Lin LLNL X-ray Raman spectroscopy October 29, 2005 X. Qin University of Hawaii XRD studies Novemver 1-7, G. Amulele 2005 J. Balogh J. Shu Carnegie Silicate post-perovskite: XRD November 6-11, 2005 W. Luo JHU Amorphous alloys November 10- H. Sheng 11, 2005 X. Chen Carnegie High Pressure Structural Study of Silane and November 12, Germane 2005 C. Jin Chinese Academy of X-ray Raman spectroscopy November 15- Science 18, 2005 D. Dattelbaum LANL Polymers XRD November 16- L. Sanchez 19, 2005 M. Pravica University of Nevada Iron: NRIXS November 16- – Las Vegas 18, 2005 R. Sander LANL Quantum Dots: XRD November 16- K. Zhuravlev 19, 2005 J. Pietryga H. Cynn LLNL Synchrotron Mössbauer spectroscopy November 17- 21, 2005 J. Z. Jiang Zhe Jiang University The atomic structure of Ti elemental metallic November 20, glass 2005 V. Struzhkin Carnegie NFS November 23- 28, 2005 Olga Degtyareva Carnegie XRD on elements November 22- 27, 2005 Valentina Degtyareva Carnegie XRD on alloys November 22- S. Kharlamova XFD/APS 27, 2005 M. Somayazulu Carnegie XRD on S/Se/As November 22- 24, 2005 A. Gavriliuk Carnegie NFS November 23- 28, 2005 J. McClure University of Nevada BM-D commissioning experiments November 28- – Las Vegas December 9, 2005 O. Tschauner University of Nevada X-ray Raman spectroscopy December 2-3, M. Pravica – Las Vegas 2005 R. Kumar N. Phatak Florida International High pressure study of iron oxide: XRD December 7-9, University 2005

103 W. Evans LLNL Low-Z materials: XRD December 8-13, M. Lipp 2005 G. Lee H. Cynn Z. Jenei B. Maddox LLNL Eu and EuN December 10, 2005 C. S. Yoo Cornell University Resistive heating experiment December 14, 2005 O. Tschauner University of Nevada X-ray emission spectroscopy December 13, – Las Vegas 2005 W. Mao LANL X-ray emission spectroscopy of (Fe,Mg)SiO3 December 16, at high pressure 2005

M. Jacobsen University of Nevada Comissioning experminets in BM-D December 16- – Las Vegas 19, 2005 P. Zinin University of Hawaii C3N4, superhard materials: NFS December 19- J. Balogh 20, 2005 L. MIng M. Pravica University of Nevada EOS studies on PETN XRD in BM-D December 19- Z. Quine – Las Vegas 21, 2005 E. Romano D. Hartnett B. Yulga H. Giefers H. P. Liermann HPCAT Commissioning of BM-D January 31, 2006 J. F. Lin LLNL Electronic spin transition of iron in February 6, magnesiowustite – (Mg,Fe)O at high 2006 pressures and high temperature S. Merkel University of High pressure deformation of MgSiO3 February 7, L. Miyagi California – Berkeley post-perovskite 2006 S. Speziale A. Kubo Princeton X. Hong University of Chicago X-ray diffraction and absorption of February 9-10, amorphous GeO2 under pressure 2006 R. Kumar University of Nevada High pressure nuclear inelastic scattering February 10, – Las Vegas experiments on Fe-Si alloys at ambient and 2006 P. Chow HPCAT low temperatures G. Chesnut LANL High pressure XRD of metals and February 12, D. Dattlebaum Polymers; 2006 L. Sanchez Teflon, titanium and its alloy, copper, tungsten L. Ehm State University of Structure of liquid Iodine at high pressure February 12- New York, Stony and temperature 14, 2006 Brook N. Cunningham University of Multimegabar Structural transformations in February 15- A. Stemshorn Alabama – Heavy Rare Earth Metal Terbium 17, 2006 W. Qiu Birmingham H. Giefers University of Nevada Phonon density of states in Fe-Sn and Fe-Dy February 15- M. Pravica – Las Vegas compounds under high pressure 19, 2006

S. Gramsch Carnegie High pressure EOS of FeAlO3 February 19, 2006 R. Chellappa University of Nevada High pressure synchrotron diffraction studies February 19- W. M. Chien – Reno on LiAlH4 20, 2006 J. Jackson ANL Synchrotron Mössbauer spectroscopy of February 22, mantle minerals at high pressure 2006

104 Wendy Mao LANL High-pressure/temperature study of Fe-Mg February 22, H. K. Mao Carnegie silicate in post-perovskite phase 2006 J. Shu Jennifer Jackson J. Crowhurst LLNL Determination of the high-pressure melting February 24, A. Goncharov curve of iron and the structure of liquid iron 2006 M. Brown using angle-dispersive x-ray diffraction M. Lucas California Institute of FeAl vacancy effects in vibrational entropy February 26, I. Halevy Technology by inelastic nuclear resonant x-ray 2006 scattering Kimberly Tait LANL High P-T phase relationships of first row February 26, transition metal monosulfides 2006 Wendy Mao LANL X-ray diffraction studies of (Mg, Fe)SiO3 post February 26- H.K. Mao Carnegie perovskite at high pressure and high 27, 2006 J. Shu temperatures H. P. Liermann Florida Institutional Compression of high-pressure standards (MO) March 5, 2006 University at high-pressure and temperature in resistive heated DAC S. V. Raju Florida Institutional Comprression opf high-pressure standards March 9-11, S. Kulkarni University (Mo) at high pressure and temperature in 2006 resistivelly heated DA R. Dinnebin MPI Solid State High Pressure XRPD March 10, 2006 Research H. Liu HPCAT Mechanisms responsible for pressure induced March 11, 2006 phase transitions in ZnO B. Hinrichsen Max Planck Institut Mechanism responsible for pressure induced March 11-13, R. Dinnebier für phase transition in ZnO and other binary and 2006 K. Sugimoto Festkörperforschung temary oxides J. McClure University of Nevada Testing of Laue and EDX approach to SXD March 15, 2006 – Las Vegas experiments at high pressure C. S. Yoo LLNL Studies of structural transition in low-Z March 15, 2006 H. Cynn compounds M. Lipp W. Evans J. P. Perrillat University of Illinois – X-ray Raman spectroscopy March 15-24, D. Lakshtanov Urbana Champaign 2006 P. Dera Carnegie Testing of Laue and EDX approach to SXD March 15-19, experiments at high pressure 2006 S. Sinogeikin HPCAT Raman spectroscopy March 21, 2006 B. Downs University of Arizona Single crystal diffraction: BM-D March 21-25, 2006 P. Dera Carnegie Single crystal diffraction: BM-D March 21-25, 2006 J. Shu Carnegie Silicate post-perovskite: XRD March 23-30, 2006 H. K. Mao Carnegie X-Ray diffraction of H2O at high pressures March 25, 2006 J. Shu Wendy Mao LANL Jennifer Jackson Carnegie X-ray diffraction on mantle minerals at March 25-26, high-pressure 2006 Jennifer Ciezak Carnegie HIgh Pressure Crystallographic Analysis of March 29-31, Sodium Azide; 2006 Raman spectroscopy H. K. Mao Carnegie X-ray Raman spectroscopy March 30-31, 2006 C. Gobin University of Nevada 16ID-B XRD March 30-31, – Las Vegas 2006

105 J. McClure University of Nevada Powder diffraction studies on low-Z and March 31-April O. Tschauner – Las Vegas high-Z oxides 2, 2006 A. Bommannavar HPCAT NFS studies of gamma Fe2O3 nanoparticles April 1-2, 2006 under high pressure; Raman spectroscopy B. Yulga University of Nevada 16-ID-B XRD April 2-3, 2006 Z. Quine – Las Vegas M. Pravica R. Kumar University of Nevada Low temperature x-ray diffraction studies on April 5, 2006 – Las Vegas CeCu2Si2, Ag, Au and Pt under pressure C. S. Yoo LLNL Powder diffraction in 16-ID-B April 5-6, 2006 H. Cynn Raman spectroscopy W. Evans M. Lipp V. Struzhkin Carnegie Effect of broadening of spin-crossover tuned April 5-10, by pressure in transition metal oxides; 2006 Raman spectroscopy A. Goncharov Carnegie 16-ID-B, XRD April 10, 2006 Kimberly Tait LANL Compressive yield strength measurements of April 11, 2006 P. Liermann Carnegie novel metals in the DAC Yue Meng Carnegie Pressure-induced spin transition in iron April 12,2006 nitrides J. Shu Carnegie Silicate post-perovskite: XRD April 13, 2006 A. Lazicki LLNL High pressure magnetic properties of light April 14, 2006 B. Maddox rare-earths using XES H. Giefers University of Nevada 16IDB XRD April 14-16, – Las Vegas 2006 C. Gobin University of Nevada 16IDB, XRD; Raman spectroscopy April 14-17, – Las Vegas 2006 R. Kumar University of Nevada High pressure x-ray diffraction studies of April 17, 2006 – Las Vegas Telluride and hydride compounds Patricia Kalita University of Nevada High pressure studies of Bi2Se3 and Sb2Se3; April 15-17, M. Jacobsen – Las Vegas Raman spectroscopy 2006 J. McClure B. Maddox LLNL Resonant x-ray inelastic scattering in April 18, 2006 A. Lazicki compressed rare earths

P. Dera Carnegie Test of a new approach to high pressure April 19-22, white beam Single-crystal diffraction and 2006 ESAFS with rare-earth Metal organic crystals Lauren Barkoski George Washington BMD April 19-22, University 2006 Kimberly Tait LANL Compression behavior of Hafnon and Sulfides April 22-24, at high pressure and temperature in a 2006 resistive heated DAC. Compression measurements of Thorite at ambient temperature in DAC A. Bommannavar HPCAT Raman spectroscopy May 29, 2006 M. Hu N. Velisavljevic LANL High pressure x-ray diffraction of metals and June 1-3, 2006 Dana Dattlebaum polymers S. Sinogeikin HPCAT Raman spectroscopy June 3, 2006 H. K. Mao Carnegie Raman spectroscopy June 3, 2006 Wendy Mao LANL S. Sinogeikin HPCAT Raman spectroscopy June 7-9, 2006 V. Prakapenka GSECARS High-temperature studies June 7-9, 2006 A. Kuznetsov

106 L. Gao University of Illinois – High pressure effect on orbital ordering in June 9-13, J. Wang Urbana-Champaign transition metal oxides; 2006 C. Bin Raman spectroscopy S. Parsons University of Sample lab and ruby, organic project June 2006 S. Moggach Edinburgh

Y. Ding HPCAT High pressure effect on orbital ordering in June 9-11, Y. Ren ANL transition metal oxides 2006

M. Lucas California Institute of Fe-Ni alloys: XRD June 14-19, Technology 2006 E. Romano University of Nevada Radiation-induced decomposition of energetic June 16-19, B. Olson – Las Vegas – materials 2006 J. Larson HIPSEC T. Hirschauer B. Walters Z. Quine A. Goncharov Carnegie Study of the EOS and structure June 16-20, of low-Z materials 2006 H. Giefers University of Nevada Commissioning in BM-B June 16-19, – Las Vegas 2006 J. Liu Chinese Academy of High pressure induced phase transitions for June 17-18, Y. Li Sciences rare earth compounds 2006 H. Liu HPCAT S. Merkel University of Simultaneous high-pressure and temperature June 21, 2006 California – Berkeley investigation of memory effects in the phase transitions of iron S. Gramsch Carnegie PbTiO3 at high pressure and low June 21-22, M. Ahart temperature 2006 R. Kumar UNLV Heavy fermion materials: XRD June 21-24, 2006 Y. Li ESRF XRD June 25, 2006 C. D. Martin State University of NaMgF3 at high pressure: XRD June 23-24, New York, Stony 2006 Brook H. K. Mao Carnegie X-ray diffraction of deuterated H2 at high June 24-30, J. Shu pressure ID-B; 2006 Wendy Mao LANL Raman spectroscopy V. Struzhkin Carnegie XRD June 26-30, Raman spectroscopy 2006 L. Jing ESRF XRD June 26, 2006 P. Dera Carnegie Tests of oscillation Laue analysis approach to June 28-July 5, structure solution from white beam 2006 Lauren Borkowski University of Nevada diffraction BM-D – Las Vegas B. Lavina UNIPD B. Yulga University of Nevada Single crystal diffraction of epsilon oxygen July 1-2, 2006 E. Romano – Las Vegas and nitrogen under high pressure BM-B/D K. Zhuravlev LANL Quantum dots under pressure: XRD July 1-3, 2006 N. Cunningham University of High pressure x-ray diffraction of metals July 3-7, 2006 W. Qiu Alabama – ID-B/BM-B N. Velisavljevic Birmingham J. Pietryga LANL XRD July 1-3, 2006 Kimberly Tait LANL High P-T phase July 5-7, 2006 relationships of first Row transition metal monosulfides ID-B, DAC XRD H. Giefers University of Nevada X-ray emission spectroscopy July 5-10, 2006 – Las Vegas

107 H. Scott Indiana University – High pressure EOS of Fe3P July 7-9, 2006 S. Huggins South Bend (ID-B) L. George FIU High pressure and temperature study of MAX July 7-10, 2006 S. Vennila hydrides and perovskite XRD in BM-D Jennifer Jackson Carnegie Raman spectroscopy July 10, 2006 M. Jacobsen University of Nevada High pressure characterization of Bi2Se3, July 13-14, J. Baker – Las Vegas SbTe3, and solid solution 50/50 Bi2Te3/Sb2Te3 2006 E. Baxter ID-B J. Keen Patricia Kalita University of Nevada ID-B and Raman spectroscopy July 12-14, – Las Vegas 2006 J. McClure University of Nevada ID-B and Raman spectroscopy July 15-18, – Las Vegas 2006 H. Giefers University of Nevada ID-B and Raman spectroscopy July 15-17, – Las Vegas 2006 Lee Seoul National Raman spectroscopy July 17, 2006 S. Keun University P. Dera Carnegie Single crystal diffraction commissioning in July 19-22, BM-B 2006 P. Shafe UNLV Visitors July 17, 2006 B. Huberti L. Fiorenino V. Iota LLNL Bonding changes in compressed molecular July 19, 2006 solids W. Evans LLNL Ambient and high-temperature crystal July 19-23, structures, phase transitions and equations 2006 of state of materials at high pressures by EDXD O. Tschauner UNLV XRD in BM-B July 19-20, 2006 C. Gobin UNLV XRD in BM-B July 18-20, 2006 W. Xiao Chinese Academy of Raman system and ID-B July 21, 2006 Sciences Wendy Mao LANL High P-T study of Fe-Mg silicate in post- perovskite phase; July 23, 2006 Raman spectroscopy Lauren Borkowski University of Nevada Single crystal diffraction commissioning in July 26-29, – Las Vegas BM-D 2006 M. Lipp LLNL f-metal behavior at high pressures and high July 26-31, B. Baer temperatures using DAC 2006

J. McClure University of Nevada OLA diffraction study of Cr2O3 July 26-31, – Las Vegas 2006 P. Dera Carnegie C. S. Yoo LLNL f-metal behavior at high pressures and high July 25-31, temperatures using DAC 2006

J. Shu Carnegie Commissioning in BM-D July 26-31, 2006 J. Liu Chinese Academy of XRD July 21-27, Sciences 2006 W. Xiao GIG ID-B diffraction July 23-26, 2006 X. Li Chinese Academy of High-pressure behavior of some rare earth July 29-30, Sciences sesquioxides 2006 B. Yulga University of Nevada Angular-dispersive x-ray studies of organic August 3, 2006 – Las Vegas materials

108 Patricia Kalita University of Nevada High-pressure investigations of TiH2 August 4, 2006 – Las Vegas R. Kumar University of Nevada Structural studies of silicides and hydrides August 4, 2006 – Las Vegas under pressure

B. U2A Infrared Beamline (NSLS) Beamline U2A is managed by Carnegie and provides useful materials characterization capabilities not available at other beamlines. The principal source of support for this beamline is the National Science Foundation, through the EAR COMPRES consortium. CDAC has a 20% membership in the facility by virtue of Carnegie management. CDAC provided partial salary support for Beamline scientist Zhenxian Liu as well as beamline upgrades and supplies. (Experiments denoted by an asterisk were carried out by the beamline scientist for the group).

User Name Affiliations Project Dates B. Chen University of High pressure XRD and IR study of August 1-4, California – polytypically disordered nano-ZnS 2005 Berkeley G. Lager University of High-pressure infrared studies of August 10-13, Louisville hydrogarnet and OH-topaz 2005 J. Bass University of Illinois Quantitative analysis of hydrogen content of August 15-22, J. Wang – Urbana-Champion high pressure phases and its effect on elastic 2005 C. Sanchez-Valley properties T. Zhou New Jersey Institute Infrared and Raman spectroscopic studies of August 25-27, of Technology FeS under high pressure 2005 H. Long SUNY – Stony Brook Investigation on cell assemblies for mantle August 29, rheology 2005 Z. Liu Carnegie Beamline development September 1- 27, 2005 L. Wang SUNY – Stony Brook IR studies of olivine September 28- 29, 2005 M. Pravica University of Nevada Infrared spectroscopy on energetic materials October 5-9, O. Tschauner – Las Vegas at high pressure and on shock synthesized 2005 M. Nicol glasses properties B. Yulga C. Gobin N. Hyatt University of High-pressure Raman and infrared studies October 11-15, J. Hriljac Sheffield of layered perovskites 2005 M. Colligan Uniersity Birmingham

B. Chen University of High pressure XRD and IR study of October 27-30, H. Zhang California – polytypically disordered nano-ZnS 2005 Berkeley November 2-3, 2005 Wren Montgomery University of Synchrotron FTIR studies of cyanuric acid November 6, California – 2005 Berkeley H. Jung University of Effect of pressure on slip system of olivine November 7, California – 2005 Riverside J. Zhang University of Synchrotron IR studies of water in eclogite November 8, California – 2005 Riverside S. Jacobsen Carnegie A synchrotron-IR study of OH in silicate November 10- Z. Liu perovskite 11, 2005 C. Melendres Université de In-situ synchrotron far infrared spectroscopy November 14- F. Hahn Poitiers at microelectrodes 22, 2005

109 J. Smedley Brookhaven Characterization of impurities in diamond January 10, 2006 P. Allen SUNY – Stony Brook Light absorption by Fe impurities in MgO at January 16- T. Sun high pressure 20, 2006 T. Yu J. Tse University of High-pressure infrared study of a lubricant January 27- Saskatchewan additive – ZDDP 29, 2006 Y. Song University of Western Ontario G. Lager University of Affect of x- and z-site substitutions on the January 30- Louisville high-pressure behavior of hydrogarnet Feb. 3 Z. Liu 2006 Carnegie February 9, 2006 X. Chen Carnegie High-pressure optical spectroscopy of February 10- A. Goncharov hydrogen-based electron materials 12, 2006 Jennifer Ciezak Carnegie High-pressure vibrational characterization February 14- T. Jenkins of energetic materials 16, 2006 D. Dolan Sandia Characterizing the emissivity of materials February 17- M. Madlener under dynamic compression 18 R. Hacking P. Allen SUNY – Stony Brook Light absorption by Fe impurities in MgO at February 27- T. Sun high pressure March 2, 2006 T. Yu Heather Watson Carnegie Synchrotron-IR measurement of OH in Al- March 3-6, bearing silicate perovskite 2006 M. Pravica University of Nevada Infrared spectroscopy on energetic materials March 9-12, M. Nicol – Las Vegas at high pressure and on shock synthesized 2006 B. Yulga glasses properties C. Gobin T. Zhou New Jersey Institute Infrared and Raman spectroscopic studies of March 13-17, Z. Qin of Technology FeS under high pressure 2006 Q. Cui Jilin University High-pressure infrared studies on Se, Te, March 18-19, AlN and C3N4 2006 C. Seagle University of Chicago The spectral emissivity and conductivity of March 28-31, D. Heinz iron from reflectance measurements at high 2006 pressure T. Tyson New Jersey Institute High-pressure Raman scattering April 5-7, P. Gao of Technology measurements on manganites 2006 J. Smedley Brookhaven Characterization of impurities in diamond April 14, 2006 T. Zhou New Jersey Institute Infrared and Raman spectroscopic studies of April 24-28, Z. Qin of Technology FeS under high pressure 2006 Gianluca Iezzi Università di Chieti The high-pressure behavior of amphiboles May 26-29, G. D. Ventura Università di Roma 2006 T. Tyson New Jersey Institute Exploring strain effects in manganite films June 1-5, 2006 P. Gao of Technology with infrared spectroscopy G. Lager Univeristy of Affect of x- and z-site substitutions on the June 6-9, 2006 Louisville high-pressure behavior of hydrogarnet J. Smedley Brookhaven Characterization of impurities in diamond June 14-15, 2006 O. Tschauner University of Nevada Infrared spectroscopy on energetic materials July 12-15, B. Yulga – Las Vegas at high pressure 2006 C. Gobin A. Gordon S. Jacobsen Carnegie Synchrotron-IR measurement of OH in Al- July 17-20, Heather Watson bearing silicate perovskite 2006 Frances Reid Carleton College

110 X. Chen Carnegie High-pressure optical spectroscopy of July 27-29, Z. Liu hydrogen-based electron materials 2006 B. Chen University of High Pressure XRD and IR Study of August 1-6, H. Zhang California – polytypically disordered nano-ZnS 2005 M. Kruger Berkeley V. S. M. Dharmaraj University of Missouri D. Dolan Sandia Characterizing the emissivity of materials August 9-13 M. Madlener under dynamic compression R. Hacking D. D. Kluge National Research High-pressure low-temperature studies of August 14-20 Council of Canada novel clathrate hydrates J. Tse University of Saskatchewan

P. Allen SUNY – Stony Brook Light absorption by Fe impurities in MgO at August 25-31 T. Sun high pressure T. Yu

C. X17 (NSLS) This facility is not supported by CDAC, but provides additional x-ray diffraction capabilities that supplement those available at HPCAT. The X17 facility consists of X17C, the superconductor wiggler beamline, the first dedicated high-pressure x-ray beamline in the world, and X17B, a dedicated beamline for variable temperature (cryogenic to laser heating) diffraction. These beamlines are supported by the National Science Foundation through the EAR COMPRES consortium and are managed by Carnegie. CDAC Academic and National Lab Partner experiments that do not require HPCAT facilities are given beam time on X17 through the Carnegie PRT allocation if they are not awarded beam time through the NSLS General User Proposal program. User support is provided by beamline scientists Jingzhu Hu (X17B) and Quanzhong Guo (X17C).

User Name Affiliations Project Dates J. Hu University of August 3-9, Chicago 2005 B. Li SUNY – Stony Brook Elastic wave velocity of mantle silicates August 6-8, 2005 Y. Ma Texas Tech High pressure study of tetragonal boron B- August 11-21, R. Aksoy University 192 2005 E. Selvi S. Lundin Massachusetts Laser heating August 25-28, J. Santillan Institute of 2005 Technology D. Shim Massachusetts Crystal structure and crystal chemistry of August 25-29, S. Lundin Institute of perovskite-structured materials at high 2005 J. Santillan Technology pressures S. Rekhi Q. Guo Geolab 4-Laue mono August 30- September 10, 2005 Zhu Mao Princeton University Single crystal x-ray diffraction and Brillouin September 10-14 F. Jiang scattering of minerals at high pressures 2005 B. Chen University of The compressibility, surface energy, and September 14- M. Finnegan California – phase stability of nano-titania 18, 2005 Berkeley J. Shu Carnegie Study of micro-minerals in eclogite and September 21- peridotite of ultrahigh pressure metamorphic 24, 2005 belt in Donghai, Jiangsu Province, China

111 Y. Ma Texas Tech Laser heating September 24- J. Sandhu University 28, 2005 F. Zhang Florida International Structural investigation of defect pyrochlores September 28- University at high pressures October 1, 2005 J. Xu Carnegie Structure of single-crystal wüstite (FeO) October 4-7, under high pressures 2005 J. Chen SUNY – Stony Brook Liquid phase transition at high pressure and October 9-14, high temperature 2005 W. Qiu University of Crystal structure and compressibility of October 10-15, J. Griffith Alabama – transition metal nanoparticles under high 2005 N. Cunningham Birmingham pressures and high temperatures B. Chen University of High pressure XRD and IR study of October 26- California – Berkeley polytypically disordered nano-ZnS November 1, 2005 S. Sen University of Structure of single-crystal wüstite (FeO) November 7-11, S. Gaudio California – Davis under high pressures 2005 T. Duffy Princeton University EOS and phase transitions in mantle November 10- minerals 15, 2005 H. Rong Institute of Geology, X-ray and infrared studies of inclusions in November 11- CAGS (China) diamond from chromite of harzburgite, 20, 2005 J. Shu Carnegie ophiolite, Tibet, China I. Halevy California Institute High pressure study of the low February 15- J. Purewall of Technology compressibility Hf-Ir, Metallic properties 19, 2006 O. Delaire crystallographic and electronic structure M. Lucas T. Duffy Princeton University Laser heating February 24- F. Jiang 27, 2006 Zhu Mao J. Santillan Massachusetts Institute of Technology F. Zhang University of Structural investigation of defect pyrochlores March 7-9, Michigan at high pressures 2006 T. Duffy Princeton University EOS and Laser heating March 7- Zhu Mao March 13, F. Zhang 2006 C. Jin Physics Institute of Pressure induced structure evolution of novel March 9-11, CAS strongly correlated perovskite system 2006 Ca1-xSrxMO3 (M=Cr,Fe,Mn) Q. L. Cui Jilin University Phase transitions and properties study of March 11-16, earth’s upper mantle mineral under 2006 high pressure and high temperature Y. Ma Texas Tech High pressure study of tetragonal boron March 17-20, University B-192 2006 Michelle University of Strength measurements of new ultrahard March 29-April Weinberger California – Los materials by radial diffraction 3, 2006 Abby Kavner Angeles Q. Guo University of Chicago X-ray and laser system setup April 3-30, 2006 I. Halevy California Institute of High pressure properties of hydrogen- April 4-8, 2006 J. Dodd Technology amorphized RCo2HX H. Rong Institute of Geology Study of micro-minerals in eclogite and April 8-17, CAGS, (China) peridotite of ultrahigh pressure metamorphic 2006 J. Shu Carnegie belt in Donghai, Jiangsu Province, China G. Hulber Naval Research In situ EDXRD of the structural changes in April 20-28, V. Cestone Laboratory PdDx for x>0.90 2006 D. Kies D.Dominguez

112 J. Chen SUNY – Stony Brook Liquid phase transition at high pressure and May 2-8, 2006 T. Yu high temperature L. Ehm Michelle California Institute Strength measurements of new ultrahard May 5-7, 2006 Weinberger of Technology materials by radial diffraction I. Halevy California Institute Large vacancy concentrations in iron- May 31-June 5, J. Dodd of Technology aluminum alloys, crystallographic and 2006 thermodynamic properties under high pressure T. Duffy Princeton University EOS and laser heating June 5-10, Zhu Mao 2006 F. Zhang I. Halevy California Institute of High pressure effect on crystallographic June 7-12, 2006 M. Lucas Technology properties of vanadium alloying J. Hu University of Chicago July 14-16, 2006 S. Jacobsen Carnegie Perovskite July 17-18, F. Reid Carleton College 2006

S. Sandeep NSLS In (OH)2 July 20-24, 2006 J. Wang National Cheng Kung H2BO3 July 26-31, University 2006 C. Bin University of The compressibility, surface energy, and August 1-7, M. Kruger California – phase stability of nano-titania 2006 V. Dharmaraj Berkeley University of Missouri F. Zhang University of Structural investigation of defect pyrochlores August 2-7, Michigan at high pressures 2006 J. Xu Carnegie Structure of single-crystal wüstite (FeO) August 10-16, under high pressures 2006 Q. Guo University of Optical table and laser system re-setup August 10- Chicago September 10, 2006 D. Klug NRCC, Saskatchewan High-pressure low-temperature studies of August 16-18, J. Tsei novel clathrate hydrates 2006 E. Selvi Texas Tech High-pressure x-ray diffraction study of the August 18-25, R. Aksoy University giant dielectric constant material 2006

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