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Energy landscapes of planar colloidal clusters.

Morgan JW, Wales DJ - Nanoscale (2014)

Bottom Line: The short-ranged potential is found to favour close-packed structures, with the potential energy primarily controlled by the number of nearest neighbour contacts.In the case of quasi-degeneracy the free energy global minimum may differ from the potential energy global minimum.This difference is due to symmetry effects, which result in a higher entropy for structures with lower symmetry.

View Article: PubMed Central - PubMed

Affiliation: University Chemical Laboratories, Lensfield Road, Cambridge CB2 1EW, UK.

ABSTRACT
A short-ranged pairwise Morse potential is used to model colloidal clusters with planar morphologies. Potential and free energy global minima as well as rearrangement paths, obtained by basin-hopping global optimisation and discrete path sampling, are characterised. The potential and free energy landscapes are visualised using disconnectivity graphs. The short-ranged potential is found to favour close-packed structures, with the potential energy primarily controlled by the number of nearest neighbour contacts. In the case of quasi-degeneracy the free energy global minimum may differ from the potential energy global minimum. This difference is due to symmetry effects, which result in a higher entropy for structures with lower symmetry.

No MeSH data available.


The variation of energy along the integrated path length for the paths including transition states IV, VII and VIII in the six-particle cluster.
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fig5: The variation of energy along the integrated path length for the paths including transition states IV, VII and VIII in the six-particle cluster.

Mentions: To compare the different mechanisms, the plots of the energy along the integrated path length for the rearrangements including transition states IV, VII and VIII are shown in Fig. 5; the energies are clearly very similar. For longer-range potentials, the partial bonding across the centre of the square in the transition state for a DSD pathway reduces the energy and makes the path more favourable. With this short-ranged potential, the bonding interactions across the square are negligible, as we see from the energies of the transition states in Table 1. Since each pathway involves the breaking of one nearest-neighbour contact, and then the formation of another, the energetics of the pathways are similar.


Energy landscapes of planar colloidal clusters.

Morgan JW, Wales DJ - Nanoscale (2014)

The variation of energy along the integrated path length for the paths including transition states IV, VII and VIII in the six-particle cluster.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263186&req=5

fig5: The variation of energy along the integrated path length for the paths including transition states IV, VII and VIII in the six-particle cluster.
Mentions: To compare the different mechanisms, the plots of the energy along the integrated path length for the rearrangements including transition states IV, VII and VIII are shown in Fig. 5; the energies are clearly very similar. For longer-range potentials, the partial bonding across the centre of the square in the transition state for a DSD pathway reduces the energy and makes the path more favourable. With this short-ranged potential, the bonding interactions across the square are negligible, as we see from the energies of the transition states in Table 1. Since each pathway involves the breaking of one nearest-neighbour contact, and then the formation of another, the energetics of the pathways are similar.

Bottom Line: The short-ranged potential is found to favour close-packed structures, with the potential energy primarily controlled by the number of nearest neighbour contacts.In the case of quasi-degeneracy the free energy global minimum may differ from the potential energy global minimum.This difference is due to symmetry effects, which result in a higher entropy for structures with lower symmetry.

View Article: PubMed Central - PubMed

Affiliation: University Chemical Laboratories, Lensfield Road, Cambridge CB2 1EW, UK.

ABSTRACT
A short-ranged pairwise Morse potential is used to model colloidal clusters with planar morphologies. Potential and free energy global minima as well as rearrangement paths, obtained by basin-hopping global optimisation and discrete path sampling, are characterised. The potential and free energy landscapes are visualised using disconnectivity graphs. The short-ranged potential is found to favour close-packed structures, with the potential energy primarily controlled by the number of nearest neighbour contacts. In the case of quasi-degeneracy the free energy global minimum may differ from the potential energy global minimum. This difference is due to symmetry effects, which result in a higher entropy for structures with lower symmetry.

No MeSH data available.