Vibrational dynamics and stability of the high-pressure chain and ring phases in S and Se.

The high-pressure phases of group-VI elements sulfur and selenium in their spiral chain and ring structures are examined by in situ Raman and x-ray diffraction techniques combined with first principles electronic structure calculations. The S-II, S-III, Se-I, and Se-VII having spiral chain structures and S-VI with a molecular six-member ring structure are studied in a wide P-T range. The square spiral chain structure of S-III and Se-VII is characterized by seven Raman modes that harden with increasing pressure. The calculations reproduce the observed frequencies and allow the authors to make the mode assignment. The "p-S" and "hplt" phases of sulfur reported by previous Raman studies are identified as S-II and S-III with the triangular and square spiral chain structures, respectively. The phase relations obtained by the x-ray and Raman measurements show that the high-pressure high-temperature phases of sulfur, observed by x-ray, can be induced by laser illumination at room temperature.

[1]  Hans Wondratschek,et al.  Bilbao Crystallographic Server. II. Representations of crystallographic point groups and space groups. , 2006, Acta crystallographica. Section A, Foundations of crystallography.

[2]  M. Mezouar,et al.  Alternating sequence of ring and chain structures in sulphur at high pressure and temperature , 2005, Nature materials.

[3]  R. Hemley,et al.  Crystal structure of sulfur and selenium at pressures up to 160 GPa , 2005 .

[4]  H. Mao,et al.  Novel chain structures in group VI elements , 2005 .

[5]  M. Hanfland,et al.  Incommensurate sulfur above 100 GPa , 2005 .

[6]  H. Mao,et al.  Crystal structure of the superconducting phases of S and Se , 2005, cond-mat/0501079.

[7]  C. Hejny,et al.  Complex crystal structures of Te-II and Se-III at high pressure , 2004 .

[8]  Takahiro Yamada,et al.  Spiral chain structure of high pressure selenium − II ′ and sulfur − II from powder x-ray diffraction , 2004 .

[9]  M. W. Wong,et al.  povel isomers of hexasulfur: Prediction of a stable prism isomer and implications for the thermal reactivity of elemental sulfur. , 2004, The Journal of chemical physics.

[10]  J. Loveday,et al.  Confirmation of the incommensurate nature of Se − IV at pressures below 70 GPa , 2004 .

[11]  C. Hejny,et al.  Large structural modulations in incommensurate Te-III and Se-IV. , 2003, Physical review letters.

[12]  B. Eckert,et al.  Solid Sulfur Allotropes Sulfur Allotropes , 2003 .

[13]  B. Eckert,et al.  Molecular Spectra of Sulfur Molecules and Solid Sulfur Allotropes , 2003 .

[14]  Haozhe Liu,et al.  Pressure induced structural transitions in nanocrystalline grained selenium , 2002 .

[15]  M. Mezouar,et al.  In situ structure solution of helical sulphur at 3GPa and 400ºC , 2001 .

[16]  B. Eckert,et al.  Pressure and photo-induced phase transitions in sulphur investigated by Raman spectroscopy , 2000 .

[17]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[18]  J. Wheeldon,et al.  Infrared study of sulphur at high pressures , 1996 .

[19]  Ming,et al.  Pressure-induced phase transformations in amorphous selenium by x-ray diffraction and Raman spectroscopy. , 1996, Physical review. B, Condensed matter.

[20]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[21]  B. Eckert,et al.  Low temperature and high pressure Raman studies on crystalline S6 , 1996 .

[22]  K. Nagata,et al.  Raman spectrum of sulfur under high pressure , 1995 .

[23]  I. Orgzall,et al.  On the formation of photoinduced high pressure phases in sulfur below 10 GPa , 1995 .

[24]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[25]  Georg Kresse,et al.  Norm-conserving and ultrasoft pseudopotentials for first-row and transition elements , 1994 .

[26]  Luo,et al.  beta -Po phase of sulfur at 162 GPa: X-ray diffraction study to 212 GPa. , 1993, Physical review letters.

[27]  A. Wokaun,et al.  Phase transitions of sulfur at high pressure: Influence of temperature and pressure environment , 1993 .

[28]  W. Holzapfel,et al.  Structural Studies on Se and Te with Synchrotron Radiation to Megabar Pressures , 1993 .

[29]  T. Nishio,et al.  Raman Spectroscopic and X-Ray Diffraction Study of Sulfur under High Pressure , 1992 .

[30]  H. .. Hochheimer,et al.  Frontiers of high-pressure research , 1991 .

[31]  P. Foggi,et al.  SULPHUR AT HIGH PRESSURE AND LOW TEMPERATURES , 1991 .

[32]  A. Wokaun,et al.  Phase transitions in crystalline sulfur at p>8 GPa, observed by Raman spectroscopy in a diamond anvil cell , 1990 .

[33]  A. Wokaun,et al.  High pressure raman spectra of crystalline sulfur , 1990 .

[34]  O. Shimomura,et al.  Raman Scattering of Trigonal Se and Te at Very High Pressure , 1980 .

[35]  R. Steudel,et al.  Redetermination of the Crystal and Molecular Structure of Cyclohexasulfur, S6 [1] , 1978 .

[36]  R. H. Wentorf.  Chapter 9 – High Pressure Phenomena , 1971 .

[37]  J. Berkowitz,et al.  Vibrations and Thermodynamic Properties of Hexasulfur , 1967 .

[38]  V. Neff,et al.  The infrared and Raman spectra of S6 , 1967 .

[39]  W. Kohn,et al.  Self-Consistent Equations Including Exchange and Correlation Effects , 1965 .