High-Pressure Elastic Properties of Minerals, Glasses and Superhard Materials

Goals in 2013-2014 for Yun-Yuan Chang: Yun-Yuan will develop new gasketing methods and try to reach higher pressures for determination of the bulk modulus of BCxN. Further, Xiaobing hopes to measure the single-crystal elastic constants (Cij) of BCxN by Brillouin scattering. Yun-Yuan, who has been supported by CDAC throughout her graduate career, plans to graduate from Northwestern in the Fall of 2013 and hopes to pursue postdoctoral research in high-pressure physics at either one of NNSA’ National Labs or a University. Goals in 2013-2014 for Joshua Townsend: Synthesize OH-bearing post-perovskite at the NSLS and obtain high-pressure FTIR spectra of sufficient quality to test the H-position models generated using DFT methods. Goals in 2013-2014 for John Lazarz: Carry out high-pressure FTIR spectroscopy or singlecrystal neutron diffraction study of thaumasite to explain how changes in the hydrogen bonding in thaumasite at high-pressure result in a structure that is twice as incompressible as the low-pressure phase.