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10:37
Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Effects of quantum delocalization on structural changes in Lennard-Jones clusters
Jason Deckman1, Vladimir A Mandelshtam
1Chemistry Department, University of California at Irvine, Irvine, California 92697, USA.
The Journal of Physical Chemistry. A
|April 25, 2009
Summary
Quantum effects influence the structure of Lennard-Jones clusters. Increasing quantum delocalization (Lambda) favors disordered, liquidlike structures over symmetric, compact ones for clusters up to n=147.
Area of Science:
- Quantum Chemistry
- Materials Science
- Statistical Mechanics
Background:
- Lennard-Jones clusters (LJ(n)) are model systems for studying the behavior of atoms and molecules.
- Understanding the structural properties of these clusters is crucial for various fields, including condensed matter physics and chemical physics.
- The influence of quantum mechanics on the macroscopic properties of matter becomes significant at low temperatures and for small systems.
Purpose of the Study:
- To investigate the ground states of Lennard-Jones clusters (LJ(n)) up to n=147.
- To map the structural phase diagram as a function of the de Boer quantum delocalization length (Lambda).
- To determine how quantum effects alter the preferred structural motifs in these clusters.
Main Methods:
- Variational Gaussian wavepacket method was employed to estimate ground states.
- The de Boer quantum delocalization parameter (Lambda) was systematically varied.
- A phase diagram was constructed to visualize structural stability regions.
Main Results:
- The study identified stable structural motifs, including Mackay icosahedra, anti-Mackay icosahedra, and highly symmetric non-icosahedral structures.
- A clear trend was observed where increasing Lambda favors more disordered and diffuse structures.
- Liquidlike (disordered) structures were found to be energetically favorable at higher Lambda values.
Conclusions:
- Quantum delocalization significantly impacts the structural preferences of Lennard-Jones clusters.
- The transition from ordered to disordered structures is driven by increasing quantum effects.
- The findings provide insights into the quantum-classical transition in finite systems.
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