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Molecular Dynamics Study of the Phase Diagram of Silver Iodide

  • C. A. Rains
  • J. R. Ray
  • P. Vashishta
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 72)

Abstract

Molecular dynamics studies have been carried out to investigate structural phase transformations in AgI as the temperature is lowered below the superionic transition temperature of ≈ 420 K while holding the pressure constant at selected values. Upon lowering the temperature for pressures below 0.27 GPa the system always transformed from the superionic phase, α-AgI, into the wurtzite phase, β-AgI. Starting from the superionic phase and lowering the temperature at the pressures of 0.28, 0.29, 0.30, and 0.31 GPa, we obtained various polytypes of the same hexagonality as has been reported experimentally. At pressures above 0.32 GPa the structure obtained upon temperature lowering was always the rocksalt form of AgI in agreement with previous simulations and experiments. At pressures between 0.31 and 0.32 GPa the system did not transform but underwent sluggish distortions among unrecognizable structures over the entire time of the simulation. This “frustration” of the system near the polytype/rocksalt phase boundary may be associated with the, so called, intermediate phase mentioned in the literature.

Keywords

Pair Distribution Function Silver Iodide Rocksalt Structure Structural Phase Transformation Experimental Phase Diagram 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. [1]
    Superionic Solids and Solid Electrolytes: Recent Trends. edited by A. L. Laskar and S. Chandra, (Academic Press, New York, 1989).Google Scholar
  2. [2]
    Physics of Superionic Conductors and Electrode Materials, edited by J. Perram, (Plenum, New York, 1983).Google Scholar
  3. [3]
    S. Chandra, Superionic Solids: Principles and Applications. (North-Holland Pub. Co., Amsterdam, 1981).Google Scholar
  4. [4]
    Fast Ion Transport in Solids, edited by P. Vashishta, J. N. Mundy, and G. K. Shenoy, (North-Holland Pub. Co., Amsterdam, 1979).Google Scholar
  5. [5]
    Physics of Superionic Conductors. edited by M. B. Salamon, (Springer-Verlag, 1979).Google Scholar
  6. [6]
    Solid Electrolytes, edited by S. Geller, (Springer-Verlag, 1977).Google Scholar
  7. [7]
    Superionic Conductors. edited by G. D. Mahan and W. L. Roth, (Plenum Press, 1976).Google Scholar
  8. [8]
    B.-E. Mellander, J. E. Bowling, and B. Baranowski, Physica Scripta 22, 541 (1980).CrossRefADSGoogle Scholar
  9. [9]
    B.-E. Mellander, Phys. Rev. B 26, 5886 (1982).CrossRefADSGoogle Scholar
  10. [10]
    A. J. Majumdar and R. Roy, J. Phys. Chem. 63, 1858 (1959).CrossRefGoogle Scholar
  11. [11]
    B. L. Davis and R. L. Petersen, Crys. Latt. Def. 1, 275 (1970).Google Scholar
  12. [12]
    B. L. Davis and L. R. Johnson, Crys. Latt. Def. 5, 235 (1974).Google Scholar
  13. [13]
    P. R. Prager, Acta. Cryst. A30, 369 (1974).Google Scholar
  14. [14]
    Q. Johnson and R. N. Schock, Acta Cryst. B31, 1482 (1975).Google Scholar
  15. [15]
    P. R. Prager, Acta Cryst. A33, 25 (1977).Google Scholar
  16. [16]
    M. Parrinello and A. Rahman, Phys. Rev. Lett. 45, 1196 (1980); J. Appl. Phys. 52, 7182 (1981).CrossRefADSGoogle Scholar
  17. [17]
    M. Parrinello, A. Rahman, and P. Vashishta, Phys. Rev. Lett. 50, 1073 (1983).CrossRefADSGoogle Scholar
  18. [18]
    J. Talion, Phys. Rev. Lett. 57, 2427 (1986).CrossRefADSGoogle Scholar
  19. [19]
    J. L. Talion, Phys. Rev. B 38, 9069 (1988).CrossRefADSGoogle Scholar
  20. [20]
    J. R. Ray and P. Vashishta, J. Chem. Phys. 90, 6580 (1989).Google Scholar
  21. [21]
    K. Y. Lee and J. R. Ray, Phys. Rev. B 39, 565 (1989).CrossRefADSGoogle Scholar
  22. [22]
    M. Moody, J. R. Ray, and A. Rahman, Phys. Rev. B 35, 557 (1987).CrossRefADSGoogle Scholar
  23. [23]
    M. C. Moody, PhD thesis, Clemson University, 1985, available from University Microfilms, Ann Arbor, Michigan.Google Scholar
  24. [24]
    P. Vashishta, Solid State Ionics 18, 3 (1986).Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1993

Authors and Affiliations

  • C. A. Rains
    • 1
  • J. R. Ray
    • 1
  • P. Vashishta
    • 2
  1. 1.Department of Physics and AstronomyClemson UniversityClemsonUSA
  2. 2.Concurrent Computing Laboratory for Material Simulations, Dept. of Physics and Astronomy and Dept. of Computer ScienceLouisiana State UniversityBaton RougeUSA

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