Permanent URL to this publication: http://dx.doi.org/10.5167/uzh-36021
Santarossa, G; Vargas, A; Iannuzzi, M; Baiker, A (2010). Free energy surface of two- and three-dimensional transitions of Au 12 nanoclusters obtained by ab initio metadynamics. Physical Review B, 81(17):174205.
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The description of the conformational space generated by metal nanoparticles is a fundamental issue for the study of their physicochemical properties. In this investigation, an exhaustive exploration and a unified view of the conformational space of a gold nanocluster is provided using a Au 12 cluster as an example. Such system is characterized by coexisting planar/quasiplanar and tridimensional conformations separated by high-energy barriers. The conformational space of Au 12 has been explored by means of Born-Oppenheimer ab initio metadynamics, i.e., a molecular dynamics simulation coupled with a history dependent potential to accelerate events that might occur on a long time scale compared to the time step used in the simulations (rare events). The sampled conformations have complex, in general not intuitive topologies that we have classified as planar/quasiplanar or tridimensional, belonging to different regions of the free energy surface. Three conformational free energy basins were identified, one for the planar/quasiplanar and two for the tridimensional structures. At thermodynamic equilibrium, the planar/quasi-planar and tridimensional conformations were found to coexist, to be fluxional and to be separated by high-free-energy barriers. The comparison between the free energy and the potential energy revealed the relevance of the entropic contribution in the equilibrium distribution of the conformations of the cluster.
|Item Type:||Journal Article, refereed, original work|
|Communities & Collections:||07 Faculty of Science > Institute of Physical Chemistry|
|Deposited On:||23 Dec 2010 13:16|
|Last Modified:||14 May 2013 20:30|
|Publisher:||American Physical Society|
|WoS Citation Count:||6|
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