Mineralogy and Crystallography
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MEETINGS
FUNDING
PRESS RELEASES
 RESEARCH PAPERS FROM OUR LAB:
  1. Gibbs, G.V., Hill, F.C., Boisen, M.B., Jr., and Downs, R.T. (1998) Power law relationships between bond length, bond strength and electron density distributions. Physics and Chemistry of Minerals 25, 585-590. ( pdf file )
  2. Gibbs, G.V., Boisen, M.B., Jr., Hill, F.C., Tamada, O., and Downs, R.T. (1998) SiO and GeO bonded interactions as inferred from the bond critical point properties of electron density distributions. Physics and Chemistry of Minerals, 25,574-584. ( pdf file )
  3. Jacobsen, S.D., Smyth, J.R., Swope, R.J., and Downs, R.T. (1998) Rigid-body character of the SO 4 groups in celestite, anglesite, and barite. Canadian Mineralogist, 36, 1045-1055. ( pdf abstract )
  4. Cohen, R. E., Fei, Y., Downs, R.T., Mazin, I.I., and Isaak, D.G. (1998) Magnetic collapse and the behavior of transition metal oxides: FeO at high pressures, in High-Pressure Materials Research , R. M. Wentzcovitch et al., eds., pp. 27-37, Symposium Proceedings Vol. 499, Materials Research Society, Warrendale, Pennsylvania.
  5. Prewitt, C.T. and Downs, R.T. (1998) High-Pressure Crystal Chemistry. Reviews in Mineralogy, 37, Ultrahigh-Pressure Mineralogy: Physics and Chemistry of the Earth?s Deep Interior , Russell J. Hemley, Editor. Mineralogical Society of America, Washington DC.
  6. Gibbs, G.V., Hill, F.C., Boisen, M.B., Jr., and Downs, R.T. (1999) Molecules as a basis for modeling the force field of silica. In Structure and Imperfections in Amorphous and Crystalline SiO 2 . Rod Devine, editor, John Wiley and Sons, Chapter 6, 151-163.
  7. Downs, R.T., Yang, H., Hazen, R.M., Finger, L.W., and Prewitt, C.T. (1999) Compressibility mechanisms of alkali feldspars: New data from reedmergnerite. American Mineralogist , 84, 333-340. ( pdf file )
  8. Sprague, A.L., Roush, T.L., Downs, R.T., Righter, K. (2000) Response to comment on "Comparison of laboratory emission spectra with Mercury telescopic data" by Melissa Lane. Icarus 143, 409-411. ( pdf file )
  9. Holl, C.M., Smyth, J.R., Lausten, H.M.S., Jacobsen, S.D., and Downs, R.T. (2000) Compression of witherite to 8 GPa and the crystal structure of BaCO 3 II. Physics and Chemistry of Minerals , 27, 467-473. ( pdf file )
  10. Hazen, R.M., and Downs, R.T. (2000) High-Temperature and High-Pressure Crystal Chemistry , Reviews in Mineralogy and Geochemistry, Volume 41. Robert M. Hazen and Robert T. Downs, Editors. Mineralogical Society of America, Washington DC.
  11. Angel, R.J., Downs, R.T., and Finger, L.W. (2000) High-temperature ? high-pressure diffractometry. Reviews in Mineralogy and Geochemistry, 41, High-Temperature and High-Pressure Crystal Chemistry , Robert M. Hazen and Robert T. Downs, Editors. Mineralogical Society of America, Washington DC.
  12. Downs, R.T. (2000) Analysis of harmonic displacement factors. Reviews in Mineralogy and Geochemistry, 41, High-Temperature and High-Pressure Crystal Chemistry , Robert M. Hazen and Robert T. Downs, Editors. Mineralogical Society of America, Washington DC.
  13. Downs, R.T., and Heese, P.J. (2000) Animation of crystal structure variations with pressure, temperature and composition. Reviews in Mineralogy and Geochemistry, 41, High-Temperature and High-Pressure Crystal Chemistry , Robert M. Hazen and Robert T. Downs, Editors. Mineralogical Society of America, Washington DC.
  14. Hazen, R.M., Downs, R.T., and Prewitt, C.T. (2000) Principles of comparative crystal chemistry. Reviews in Mineralogy and Geochemistry, 41, High-Temperature and High-Pressure Crystal Chemistry , Robert M. Hazen and Robert T. Downs, Editors. Mineralogical Society of America, Washington DC.
  15. Thompson, R.M., and Downs, R.T. (2001) Quantifying distortion from ideal closest-packing in a crystal structure with analysis and application. Acta Crystallographica B57, 119-127. ( pdf file )
  16. Righter, K., and Downs, R.T. (2001) The crystal structures of synthetic Re- and PGE-bearing magnesioferrite spinels: Implications for impacts, accretion and the mantle. Geophysical Research Letters , 28, 619-622.
  17. Thompson, R.M., and Downs, R.T. (2001) The systematic generation of all nonequivalent closest-packed stacking sequences of length N using group theory. Acta Crystallographica, B57, 766-771. ( pdf file )
  18. Lager, G.A., Downs, R.T. Origlieri, M., and Garoutte, R. (2002) High-pressure single-crystal X-ray diffraction study of hydrogarnet: Evidence for a phase transition from Ia3d to I43d symmetry at 5 GPa. American Mineralogist 87, 642-647. ( pdf file )
  19. Downs, R.T., Gibbs, G.V., Boisen, M.B.Jr., and Rosso, K.M. (2002) A comparison of procrystal and ab initio representations of the electron-density distributions of minerals. Physics and Chemistry of Minerals 29, 369-385. ( pdf file )
  20. Downs, R.T. and Hall-Wallace, M. (2003) The American Mineralogist Crystal Structure Database. American Mineralogist 88, 247-250. ( pdf file )
  21. Downs, R.T. (2003) Topology of the pyroxenes as a function of temperature, pressure, and composition as determined from the procrystal electron density. American Mineralogist 88, 556-566. ( pdf file )
  22. Thompson, R.M. and Downs, R.T. (2003) Model pyroxenes I: Ideal pyroxene topologies. American Mineralogist 88, 653-666. ( pdf file )
  23. Denton, M.B., Sperline, R.P., Giles, J.H., Gilmore, D.A., Pommier, C.J.S., and Downs, R.T. (2003) Advances in the application of array detectors for improved chemical analysis, Part I. Comparison of qualitative analyses using large, computer-based Raman spectral libraries. Australian Journal of Chemistry 56, 117-131. ( pdf file )
  24. Downs, R.T. (2003) The Berry Medal for 2002 to Robert T. Downs. The Canadian Mineralogist 41, 243-245. ( pdf file )
  25. Gibbs, G.V., Cox, D.F., Boisen, M.B., Jr., Downs, R.T., and Ross, N.L. (2003) The electron localization function: a tool for locating favorable proton docking sites in the silica polymorphs. Physics and Chemistry of Minerals, 30, 305-316. ( pdf file )
  26. Origlieri, M.J., Downs, R.T., Thompson, R.M., Pommier, C.J.S., Denton, M.B., and Harlow, G.E. (2003) High-pressure crystal structure of kosmochlor, NaCrSi 2 O 6 , and systematics of anisotropic compression in pyroxenes. American Mineralogist, 88, 1025-1032. ( pdf file ) ( erratum )
  27. Wang, Z., Downs, R.T., Pischedda, V., Shetty, R., Saxena, S.K., Zha, C.S., Zhao, Y.S., Schiferl, D., and Waskowska, A. (2003) High-pressure X-ray diffraction and Raman spectroscopic studies of the tetragonal spinel CoFe 2 O 4 . Physical Review B 68, 094101. ( pdf file )
  28. Wang, Z., Zhao, Y., Schiferl, D., Zha, C.S., Downs, R.T., Sekine, T. (2003) Critical pressure for weakening of size-induced stiffness in spinel-structure Si 3 N 4 nanocrystals. Applied Physics Letters , 83, 3174-3176. ( pdf file )
  29. Pommier, C.J.S., Denton, M.B., and Downs, R.T. (2003) Raman spectroscopic study of spodumene (LiAlSi 2 O 6 ) through the pressure-induced phase change from C 2/ c to P 2 1 / c . Journal of Raman Spectroscopy , 34, 769-775. ( pdf file )
  30. Gibbs, G.V., Whitten, A.E., Spackman, M.A., Stimpfl, M., Downs, R.T., and Carducci, M.D. (2003) An exploration of theoretical and experimental electron density distributions and SiO bonded interactions for the silica polymorph coesite. Journal of Physical Chemistry B , ASAP Web Release Date: 01-Nov-2003; DOI: 10.1021/jp030583+ ( pdf file )
  31. Wang, Z., Zhao, Y., Schiferl, D., Qian, J., Downs, R.T., Mao, H-K., and Sekine, T. (2003) Threshold pressure for disappearance of size-induced effect in spinel-structure Ge3N4 nanocrystals. Journal of Physical Chemistry B Letters , ASAP Web Release Date: 02-Dec-2003; DOI: 10.1021/jp036436t ( pdf file )
  32. Ross, N.L. and Downs, R.T. (2003) "Stuffed" framework structures at high pressure. In NATO ASI Series: High-Pressure Crystallography , P.F. McMillan and A. Katrusiak, Eds., Kluwer Academic Press.
  33. Thompson, R.M., and Downs, R.T. (2004) Model pyroxenes II: Structural variation as a function of tetrahedral rotation. American Mineralogist 89, 614-628. ( pdf file )
  34. Bobev, S., and Tait, K.T. (2004) Methanol - inhibitor or promotor of the formation of gas hydrates from deuterated ice? American Mineralogist 89, 1208-1214. ( pdf file )
  35. Clark, C.M., and Downs, R.T. (2004) Using the American Mineralogist Crystal Structure Database in the classroom. Invited paper, Journal of Geoscience Education 51, 76-80. ( pdf file )
  36. Downs, R.T., and Hazen, R.M. (2004) Chiral indices of crystalline surfaces as a measure of enantioselective potential. Invited paper, Journal of Molecular Catalysis A: Chemical 216, 273-285. ( pdf file )
  37. Wang, Z, Zhao, Y., Schiferl, D., Zha, C.S., and Downs, R.T. (2004) Pressure induced increase of particle size and resulting weakening of elastic stiffness of CeO 2 nanocrystals. Applied Physics Letters 85, 124-126. ( pdf file )
  38. Wang, Z, Tait, K., Zhao, Y., Schiferl, D., Zha, C.S., Uchida, H., and Downs, R.T. (2004) Size-induced reduction of transition pressure and enhancement of bulk modulus of AlN nanocrystals. Journal of Physical Chemistry B 108, 11506-11508. ( pdf file )
  39. Wang, Z, Zhao, Y., Tait, K., Liao, X., Schiferl, D., Zha, C.S., Downs, R.T., Qian J., Zhu, Y., and Shen, T. (2004) A quenchable superhard carbon phase synthesized by cold compression of carbon nanotubes. Proceedings of the National Academy of Sciences of the United States of America 101, 13699-13702 ( pdf file )
  40. Le Bail, A., Chateigner, D., Chen, X., Ciriotti, M., Cranswick, L.M.D., Downs, R.T., Lutterotti, L., Rajan, H., Yokochi, A.F.T. (2004) Does open data better serve the crystallographic community? International Union of Crystallography Newsletter 12, 27.

 
MEETINGS: back to top
  1. Downs, R.T., Yang, H., Hazen, R.M., and Finger, L.W. (1997) The high-pressure crystal chemistry of the alkali feldspars: New data from reedmergnerite, NaBSi 3 O 8 . EOS Transactions, AGU, Spring Meeting Supplement, 78 (17) S314
  2. Cohen, R.E., Fei, Y., Mazin, I.I., Downs, R.T., and Isaak, D.G. (1997) Phase transitions in transition metal oxides and unusual polytypism in high pressure FeO. EOS Transactions, AGU, Fall Meeting Supplement, 78 (46) F743
  3. Downs, R.T., Teter, D.M., and Gibbs, G.V. (1997) A Pro-crystal electron density analysis of potassium-oxygen bonding in microcline and KTP as a function of pressure. EOS Transactions, AGU, Fall Meeting Supplement, 78 (46) F754
  4. Downs, R.T. (1998) Computer graphics simulation of compression mechanisms in crystals. IUCR-HP98, Argonne, Abstracts, 21
  5. Thompson, R.M., and Downs, R.T. (1999) Quantitative analysis of the closest-packing of anions in mineral structures as a function of pressure, temperature, and compositions. EOS Transactions, AGU, Fall Meeting Supplement, 80 (46) F1107.
  6. Downs, R.T., Gibbs, G.V., and Boisen M.B., Jr. (1999) Topological analysis of the P21/c to C2/c transition in pyroxenes as a function of temperature and pressure. EOS Transactions, AGU, Fall Meeting Supplement, 80 (46) F1140.
  7. Righter, K., and Downs, R.T. (2000) Magnesioferrite spinel as the host phase for iridium and other highly siderophile elements at the cretaceous-tertiary boundary. Meteoritical Society Meeting. Meteoritics & Planetary Science 35: A136-A137, Supplement S Sep 2000
  8. Downs, R.T., Gibbs, G.V., Giovanni, M.K., Boisen, M.B.Jr., and Rosso, K.M. (2001) A comparison of procrystal and first-principles crystal electron density distributions with application to understanding the phase changes in pyroxenes. In Eleventh Annual V.M. Goldschmidt Conference, Abstract#3902, LPI Contribution No. 1088, Lunar and Planetary Institute, Houston (CD-ROM). May 20-24, Hot Springs, VA.
  9. Thompson, R.M., Downs, R.T., and Lienert, C. (2001) Ideal Pyroxene Topologies. In Eleventh Annual V.M. Goldschmidt Conference, Abstract#3149, LPI Contribution No. 1088, Lunar and Planetary Institute, Houston (CD-ROM). May 20-24, Hot Springs, VA.
  10. Thompson, R.M., Downs, R.T., and Teter, D.M. (2001) Packing systematics of stishovite. EOS Transactions, AGU, Fall Meeting Supplement, 82 (47) F1156. ( pdf abstract )
  11. Origlieri, M.J., Downs, R.T., and Harlow, G.E. (2001) Compression mechanism of the pyroxene kosmochlor. EOS Transactions, AGU, Fall Meeting Supplement, 82 (47) F1393. ( pdf abstract )
  12. Pommier, C.J.S., Denton, M.B., and Downs, R.T. (2002) Polarized Raman spectroscopic study of the pressure-induced phase change from C2/c to P21/c in spodumene. Pittcon 1747P, New Orleans, LA, March 17-22, 2002. ( pdf file )
  13. Lager, G.A., Marshall, W.G., and Downs, R.T. (2002) Keynote address: Re-examination of the hydrogarnet structure at high pressure using neutron powder methods: Comparison with single-crystal X-ray and theoretical results. 18th General Meeting of the International Mineralogical Association , 1-6 Sept, 2002, Edinburgh, Scotland. Programme With Abstracts, page 82.
  14. Origlieri, M.J., Thompson, R.M., Downs, R.T., and Gibbs, G.V. (2002) The relationship between compression anisotropy observed in the pyroxenes and oxide anion non-bonded repulsions. 18th General Meeting of the International Mineralogical Association , 1-6 Sept, 2002, Edinburgh, Scotland. Programme With Abstracts, page 71.
  15. Downs, R.T., and Hall-Wallace, M. (2002) A Database of Crystal Structures Published in the American Mineralogist and The Canadian Mineralogist and It?s Use as a Resource in the Classroom. 18th General Meeting of the International Mineralogical Association , 1-6 Sept, 2002, Edinburgh, Scotland. Programme With Abstracts, page 128.
  16. Thompson, R.M., and Downs, R.T. (2002) Model Pyroxenes and Transition Pathways. 18th General Meeting of the International Mineralogical Association , 1-6 Sept, 2002, Edinburgh, Scotland. Programme With Abstracts, page 85.
  17. Pommier, C.J.S., Denton, M.B., and Downs, R.T. (2003) Raman spectroscopic study of spodumene through the pressure-induced phase change from C2/c to P21/c. Pittcon 1730-3, Orlando, FL, March 9-14, 2003.
  18. Ross, N.L., and Downs, R.T. (2003) High-pressure crystal chemistry: ?Stuffed? framework structures at high-pressure. International School of Crystallography , High Pressure Crystallography, 4-15 June. Erice, Italy
  19. Hazen, R.M. and Downs, R.T. (2003) Chiral mineral surfaces and their chiral index. The Geological Society of America Annual Meeting, Seattle Washington. November 2-5, 2003. ( pdf abstract )
  20. Gibbs, G.V., Whitten, A., Spackman, M., Simpfl, M., Carducci, M., and Downs, R.T. (2003) The silica polymorph coesite: An exploration of the electron density. The Geological Society of America Annual Meeting, Seattle Washington. November 2-5, 2003. ( pdf abstract )
  21. McIntosh, B., Denton, M.B., Downs, R.T., Becker, D. (2003) Smart Raman instrument for Mars Science Laboratory. Mars Exploration Program Assessment Group, Sept 10-11, Jet Propulsion Laboratory, Pasadena, CA. ( pdf file )
  22. Uchida, H., and Downs, R.T. (2003) Single-crystal X-ray diffraction studies on spinels from the San Carlos Volcanic Field, Arizona. In Geochimica et Cosmochimica Acta 67, A497 Supplement, Goldschmidt Conference, Sept 7-12, Kurashiki Japan. ( pdf file )
  23. Tait K.T., Zhao, Y., and Downs, R.T. (2004) Investigations into the stability, morphology, and crystal structure of the coexistence of s-I and s-II methane-ethane and methane-propane clathrate hydrates: occurrence and geological implications. Lab Directed Research Dollars Review at LANSCE, Los Alamos, New Mexico. March 17, 2004.
  24. McIntosh, B. Denton, M.B., and Downs, R.T. (2004) Process Raman on Earth and research Raman on Mars - How are they related? Pittcon March 11, 2004. (Session: 24300-1000). Chicago, IL.
  25. Liermann H. P., Downs R. T., Yang H. (2004) Raman spectroscopy of order/disorder in pseudobrookite (MgTi2O5): Implication for the determination of the thermal history of planetary materials by remote sensing. 32nd IGC - Florence 2004.
  26. Hazen, R.M., Asthagiri, A., Teng, H., and Downs, R.T. (2004) Geochemical pathways to the origin of biochemical homochirality. Division of Geochemistry, American Chemical Society National Meeting, Philadelphia, PA, Aug 22-26. ( html file )
  27. Downs, R.T., Liermann, H.P., and Yang, H. (2004) The analysis of Mg and Ti order/disorder in pseudobrookite by Raman spectroscopy: Implications for the geological exploration of Mars. Geological Association of Canada - Mineralogical Association of Canada Annual Meeting, St. Catherines 2004. SS01-06.

 
FUNDING: back to top
  • Capitalization, University of Arizona, (1996) $240,000.
  • A device to apply hydrostatic high-pressure to crystals (1999-2001) Faculty Small Grants Program, University of Arizona Foundation, $5000.
  • Compression mechanisms of upper mantle minerals (1999-2002) National Science Foundation, $186,997.
  • Advancing Computational and Visualization Skills in Geosciences (2000-2002) National Science Foundation, $52,148. Joint, with M. Hall-Wallace (P.I.), R. F. Butler, P. Kresan, J. Pelletier.
  • Compression mechanisms of upper mantle minerals, Research Experience for Undergraduates (2000-2002) National Science Foundation, $12,500.
  • The crystal structure database and analysis tools project (2001-2004) National Science Foundation, $350,000.
  • University of Nevada at Las Vegas subcontract (2002) Development of Windows-based single crystal diffractometer software, Department of Energy, $34,815.
  • University of Nevada at Las Vegas subcontract (2002-2003) Development of Windows-based single crystal diffractometer software for Argonne National Labs' Advance Photon Source, Department of Energy, $83,669.
  • A high performance Raman spectroscopy system for Mars surface studies. (2003-2005) Co-PI: B. McIntosh (Hamilton Sundstrand Sensor Systems), M.B. Denton (U of Arizona), R.T. Downs (UofA) and W. Doyle (Axiom Analytical, Inc.) NASA, $1,491,770.
  • Clathrate Hydrates Science and Technology. (2003-2005) PI: Yusheng Zhao (Los Alamos) Co-PI: D.L. Bish, L.L. Daemen, A. Migliori, R.P. Currier, L.R. Pratt, P.C. Lichtner, D.D. Hickmott. Collaborators: H-K Mao, R. Hemley, J. Parise, R.T. Downs. Department of Energy $4,350,000.
  • Combination of private funding and matching funds from the College of Science for a new Bruker X8Apex single-crystal diffractometer and a Bruker D8Advance powder diffractometer plus laboratory renovations, $450,000.

 
PRESS RELEASES: back to top

 

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The University Of Arizona Department Of Geosciences Mineralogy and Crystallography