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Updated: Jul 17, 2026
10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Modulated structure of solid iodine during its molecular dissociation under high pressure
Takemura Kenichi1, Sato Kyoko, Fujihisa Hiroshi
1Advanced Materials Laboratory, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan. takemura.kenichi@nims.go.jp
Nature
|June 27, 2003
Summary
High pressure transforms solid iodine into a monatomic state. Researchers discovered an intermediate, incommensurately modulated phase during this pressure-induced dissociation, revealing new insights into molecular crystal behavior.
Area of Science:
- Condensed Matter Physics
- Materials Science
- High-Pressure Physics
Background:
- Solid iodine undergoes molecular dissociation under extreme pressure.
- Previous studies suggested direct dissociation or intermediate molecular phases.
- Understanding pressure-induced phase transitions in molecular crystals is crucial.
Purpose of the Study:
- To investigate the intermediate phase during pressure-induced dissociation of solid iodine.
- To characterize the structure and properties of this transient phase.
- To elucidate the molecular-level mechanism of pressure-induced dissociation.
Main Methods:
- Quasi-hydrostatic powder X-ray diffraction measurements.
- Analysis of interatomic distances and structural modulation.
- Comparison with existing X-ray diffraction and spectroscopic data.
Main Results:
- Clear evidence of an intermediate phase during iodine dissociation.
- The intermediate phase exhibits an incommensurately modulated structure.
- Nearest interatomic distances in this phase are continuously distributed (2.86-3.11 Å).
Conclusions:
- The intermediate phase is a transient state during molecular dissociation.
- Its incommensurate structure provides insights into the dissociation mechanism.
- Further temperature-dependent studies are needed to understand its origin and stability.
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