Professor Weidner's research interests focus on mineral physics and seismology. The ultimate goals are to combine these areas to help define the physical and chemical state as well as the dynamic processes of the Earth's mantle and crust.

Weidner is currently director of the Mineral Physics Institute, of which he helped form in 1988. He has served in many roles in the department during the last several years, including deputy chairperson and coordinator for geosciences. Weidner was instrumental in organizing the graduate study advisory committee, a committee of graduate students that represents the needs of the students to the faculty, and he served as faculty advisor to this committee for several terms.

Weidner's research has included earthquake seismology, but currently focuses on using laboratory studies of Earth materials to define constraints on the state and evolution of the Earth. He pioneered an experimental technique based on Brillouin spectroscopy for determining the elastic properties of single crystals. This technique allows such measurements on both natural and synthetic materials, thus enabling the determination of acoustic properties of phases that are stable only deep in the Earth's interior. This research effort was recognized by the American Geophysical Union in awarding him the James B. Macelwane award in 1981. Currently, this technique is being extended to high pressure, with the diamond anvil cell, and to high temperature.

Weidner, along with Professors Prewitt and Liebermann, built the high-pressure facility at Stony Brook. He leads the Stony Brook large-volume, high-pressure studies with synchrotron radiation. This facility is used to determine the equation of state of Earth materials, identify phase stability fields of minerals and the yield strength of earth materials. He is the design team leader for the large-volume experiments that the GeoCARS program is preparing for the Advanced Photon Source.

Selected Publications 

Weidner, D. J., and Y. Zhao, 1992, Elasticity and equation of state of perovskite: Implications for the Earth's lower mantle, High Pressure Research: Applications to Earth and Planetary Sciences, Geophysical Monograph 67, ed Y. Syono and M. Manghnani, pub. Terra Scientific Publishing Co. and AGU, Washington D.C., 191-196.

Weidner, D. J., M. T. Vaughan, J. Ko, Y. Wang, K. Leinenweber, X. Liu, A. Yeganeh-Haeri, R. E. Pacalo, and Y. Zhao, 1992, Large volume high pressure re-search using the wiggler port at NSLS, High Pressure Research, 8, 617-623.

Weidner, D. J., M. T. Vaughan, J. Ko, Y. Wang, X. Liu, A. Yeganeh-Haeri, R. E. Pacalo, and Y. Zhao, 1992, Characterization of stress,  pressure and temperature in SAM-85, a DIA type high pressure apparatus, High Pressure Research: Applications to Earth and Planetary Sciences, Geophysical Monograph 67, ed Y. Syono and M. Manghnani, pub. Terra Scientific Publishing Co. and AGU, Washington D.C., 13-17.

Pacalo, R. E. G., D. J. Weidner, and T. Gasparik, 1992, Elastic properties of sodium-rich majorite garnet, Geophys. Res. Lett., 19, 1895-1898.

Yeganeh-Haeri, A., D. J. Weidner, and J. B. Parise, 1992, Elasticity of *-cristobalite: A silicon dioxide with a negative Poisson's ratio, Science, 257, 650-652 .

Zhao, Y., D. J. Weidner, J. B. Parise, and D. E. Cox, 1992, Critical phenomena and phase transition of perovskite--data for NaMgF ₃ perovskite: (II), Phys. Earth and Planet. Interiors, 76, 17-34.

Zhao, Y., D. J. Weidner, J. Ko, K. Leinenweber, X. Liu, B. Li, Y. Meng, R. E. G. Pacalo, M. T. Vaughan, Y. Wang, and A. Yeganeh-Haeri, 1992, Perovskite at high P-T conditions: An in-situ synchrotron X-ray diffraction study of NaMgF₃ perovskite, J. Geophys. Res., 99, 2871-2885.

Navrotsky, A., D. J. Weidner, R. C. Liebermann, and C. T. Prewitt, 1992, Materials science of the Earth's deep interior, 17, MRS Bulletin, 30-37.

Meng, Y., D. J. Weidner, and Y. Fei, 1993, Deviatoric stress in a quasi-hydrostatic diamond anvil cell: Effect on the volume-based pressure calibration, Geophys. Res. Lett., 20, 1147-1150.

Zhao, Y. and D. J. Weidner, 1993, The single crystal elastic moduli of neighborite, Phys. Chem. of Minerals, 20, 419-424.

Weidner, D. J. and H.-k. Mao, 1993, Photons at high pressure, National Synchrotron Light Source Newsletter, March, pp. 1-15.

Kusaba, K., L. Galoisy, Y. Wang, M. T. Vaughan, and D. J. Weidner, 1993, Determination of phase transition pressures of ZnTe under quasihydrostatic conditions, Pure and Applied Geophysics (PAGEOPH) in memory of Edward Schreiber (Experimental Techniques in a Laboratory), 141, in press.

Weidner, D.J., Y. Wang, Y. Meng, and M.T. Vaughan, Deviatoric stress measurements at high pressure and temperature, In Proceedings of AIRAPT/APT meeting High Pressure Science and Technology 1993, Pub. American Institute of Physics, ed: S.C. Schmidt, J.W. Shaner, G.A. Samara, M. Ross, 1025-1028.

Meng, Y., D. J. Weidner, G. D. Gwanmesia, R. C. Liebermann, M. T. Vaughan, Y Wang, K. Leinenweber, R. E. Pacalo, A. Yeganeh-Haeri, and Y. Zhao, 1993, In situ P-T X-ray diffraction studies on three polymorphs (* ,*, *) of Mg₂SiO₄, J. Geophys. Research, 98, 22,199-22,207.

Weidner, D. J., Y. Wang, and M. T. Vaughan, 1994, Yield strength at high pressure and temperature, Geophys. Res. Lett., 21, 753-756.

Kusaba, K. and D. J. Weidner, 1994, Structure of high pressure phase I in ZnTe, In Proceedings of AIRAPT/APT meeting High Pressure 
Science and Technology 1993, Pub. American Institute of Physics, ed: S.C. Schmidt, J.W. Shaner, G.A. Samara, M. Ross, 553-556.

Parise, J. B., A. Yeganeh-Haeri, D. J. Weidner, J. D. Jorgensen, and M. A. Saltzberg, 1994, Pressure induced phase transition and pressure 
dependence of crystal structure in low (*) and Ca/Al-doped cristobalite, J. Appl. Phys., 75, 1361-1367.

Zhao, Y., J. B. Parise, Y. Wang, K. Kusaba, M. T. Vaughan, D. J. Weidner, T. Kikegawa, J. Chen, and O. Shimomura, 1994, High-pressure 
crystal chemistry of NaMgF₃ perovskite: an angle dispersive diffraction study using monochromatic synchrotron x-radiation, Amer. Minealogist, 
79, 615-621.

Parise, J. B., K. Leinenweber, D. J. Weidner, K. Tan, and R. B. V. Dreele, 1994, Pressure-induced hydrogen bonding: neutron diffraction study 
of brucite, Mg(OD)₂, to 9.3 GPa, Amer. Mineral., 79, 193-196.

Wang, Y., D.J. Weidner, R.C. Liebermann, and Y Zhao, 1994, P-V-T equation of state of (Mg,Fe)SiO₃ perovskite: constraints on 
composition of the lower mantle, Phys. Earth and Planet. Interiors, 83, 13-40.

Wang, Y. and D. J. Weidner, 1994, Thermoelasticity of CaSiO ₃ perovskite and implications for the lower mantle, Geophys. Res. 
Lett., 21, 895-898.

Weidner, D.J., Y. Wang, and M.T. Vaughan, 1994, Strength of diamond, Science, in press.

Meng, Y., Y. Fei, D.J. Weidner, and J. Hu, 1994, Hydrostatic compression of g-Mg₂SiO₄ to mantle pressures and 700 K: 
constraints on the thermal equation of state and the related thermoelastic properties, submitted to Phys. Chem. Miner.

Wang, Y., I. C. Getting, D. J. Weidner and M. T. Vaughan (1996). Performance of tapered anvils in a cubic-anvil, DIA-type, 
high-pressure apparatus for in situ x-ray diffraction studies. US-Japan High Pressure Conference Submitted.

Wang, Y. and D. J. Weidner (1995). (6m/dT) of the lower mantle. Pageoph, special issue: submitted.

Wang, Y., D. J. Weidner and F. Guyot (1995). Thermal equation of state of CaSiO₃ perovskite. J. Geophys. Res. 101(B1): 661-672.