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Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
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Interplay of Intra- and Intermolecular Interactions in Solid Iodine at Low Temperatures: Experimental and Theoretic
I D Yushina1, B A Kolesov2,3
1South Ural State University , Chelyabinsk 454080 , Russia.
The Journal of Physical Chemistry. A
|May 8, 2019
Summary
Low temperature structural changes in crystalline iodine reveal unusual vibrational behavior. This is explained by strengthening intralayer halogen bonding between iodine molecules, differing from typical van der Waals crystals.
Area of Science:
- Solid-state chemistry
- Low-temperature physics
- Spectroscopy
Background:
- Crystalline iodine exhibits unique structural properties under varying temperatures.
- Understanding molecular interactions in van der Waals crystals is crucial for materials science.
Purpose of the Study:
- To investigate structural modifications in crystalline iodine at low temperatures.
- To analyze the temperature-dependent vibrational behavior of iodine molecules.
- To elucidate the role of intralayer halogen bonding in observed anomalies.
Main Methods:
- Experimental Raman spectroscopy from 5-300 K.
- Theoretical analysis of structural and vibrational properties.
- Comparison with established van der Waals crystal models (e.g., alpha-sulfur).
Main Results:
- Unusual temperature dependence observed for stretching vibrations (around 180 cm⁻¹).
- Derived temperature functions (ω(T)) for external translational and internal stretching modes of I₂.
- Significant deviation in ω(T) trends compared to alpha-sulfur.
Conclusions:
- The anomalies in crystalline iodine's vibrational modes are attributed to enhanced intralayer halogen bonding.
- This finding highlights the distinct intermolecular forces governing iodine's low-temperature behavior.
- Results provide insights into the nature of halogen bonding in condensed matter systems.
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