New phase transition of solid bromine under high pressure
A San-Miguel1, H Libotte, M Gauthier
1Université de Lyon, F-69000 Lyon, France.
Physical Review Letters
|August 7, 2007
Summary
High-pressure experiments reveal solid bromine undergoes a new phase transformation around 25 GPa. This transformation causes a significant change in intramolecular distance, with further transitions observed at higher pressures.
Area of Science:
- Condensed Matter Physics
- Materials Science
- High-Pressure Physics
Background:
- Understanding the behavior of elements under extreme pressure is crucial for materials science.
- Previous studies on solid halogens have not fully characterized phase transitions in bromine.
- X-ray absorption spectroscopy is a powerful tool for probing atomic and molecular structures under pressure.
Purpose of the Study:
- To investigate the structural phase transitions of solid bromine under high pressure.
- To determine the pressure at which new phase transformations occur.
- To analyze changes in intramolecular distances during these transitions.
Main Methods:
- Experiments were conducted using x-ray absorption spectroscopy.
- Solid bromine was subjected to pressures up to 75 GPa.
- Extended fine structure analysis was used to determine intramolecular distances.
Main Results:
- An unobserved phase transformation was identified in solid bromine at approximately 25 GPa.
- The intramolecular distance initially increased, then abruptly decreased at this transition.
- A second phase transition occurred around 65 GPa, potentially linked to an incommensurate modulated phase.
Conclusions:
- Solid bromine exhibits a novel phase transition at 25 GPa, altering its molecular structure.
- The observed phase transitions provide new insights into halogen behavior under extreme conditions.
- The findings suggest potential similar transitions may occur in other halogens.
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