Discovery of extended carbon dioxide carbonates Choong-Shik Yoo, Washington State University, DMR Project Goal: Investigate new states and novel phenomena in extreme conditions. Major findings in this year: Discovery of extended ionic carbonate phase (i-CO 3 ) in Earth mantle conditions. Determined crystal structure of i-CO 3 to be post-aragonite structure (P ) recently discovered in CaCO 3. Increase of ionic character in CO bonds at high pressure, unlike the predicted high stability of CO4-Td covalent bond to 1TPa. Strong geophysical implications to the presence of volatile CO 2 and carbon species in deep mantle conditions. Significance: These results were previously unpredicted calling attentions for new theories and have strong implications to geophysics, physics, chemistry and materials sciences. Phase/chemical transformation diagram of CO 2 (top), providing geophysical constraints for deep carbon species (bottom) ( Published in Yoo et al., Angew. Chem. Int. Ed. 50, (2011) ) i-CO 2 CO 2 CaCO 3 CO 2 -V

High-pressure behaviors of simple binary mixtures Choong-Shik Yoo, Washington State University, DMR Project Goal: Investigate interaction and phase/structural miscibility of simple binary mixtures under extreme conditions. Major findings in this year: Studies several binary mixtures of D 2 with N 2, CO 2, H 2 O, NH 3 and CH 4. Unusually high repulsive interactions resulting in high internal chemical pressure Proton exchange reactions in D 2 -H 2 O and D 2 -NH 3 mixtures, Evidence for proton ordering of D 2 -H 2 O at GPa, substantially lower than that of pure H 2 O. Novel incommensurate phase of (N 2 ) 12 D 2 formed in 9:1 N 2 :D 2 mixtures/ Evidence of interfacial reactions in CO 2 -D 2 mixtures. Significance: These results provide fundamental insights into high pressure chemistry such as repulsive interaction, phase miscibility, and internal chemical pressures (Top) Crystal structure of (N 2 ) 12 D 2 formed in N 2 :D 2 mixture ( Kim and Yoo, J. Chem. Phys. 134, (2011) ). (Bottom) Proton ordering in D 2 :H 2 O mixture between 25 and 50 GPa ( Gus and Yoo, J. Chem. Phys. 135, (2011)).

Establishing fundamental chemistry concepts: Extended solids as novel molecular alloys Bonding vs packing at high density Structure/phase miscibility vs chemical decomposition/phase separation Internal chemical pressure Developing new enabling technologies: Dynamic-DAC, capable of precise controls of pressure and compression rates, enabling high- pressure kinetic studies. Time-resolved x-ray diffraction probing structural and chemical evolutions associated with single event phenomena. Leveraging collaboration and education: Establishing a new research partnership with the HPCAT/APS, LLNL(NIF), and LANL for time- resolved x-ray diffraction under dynamic loading using dynamic-DAC. Providing six Ph.D. students and two PD’s with hands-on experience in synchrotron x-rays and high pressure technologies. Developing fundamental concepts, technologies, collaborations for high-pressure chemistry Choong-Shik Yoo, Washington State University, DMR APS NIF