Abstract
We predict the structures of neutral gas phase gold clusters at finite temperatures based on free-energy calculations obtained by replica-exchange ab initio molecular dynamics. The structures of neutral clusters are assigned at 100 K based on a comparison of experimental far-infrared multiple photon dissociation spectra performed on Kr-tagged gold clusters with theoretical anharmonic IR spectra and free-energy calculations. The critical gold cluster size at which the most stable isomer changes from planar to nonplanar is (capped-trigonal prism, ) at 100 K. However, at 300 K (i.e., room temperature), planar and nonplanar isomers may coexist even for , , and clusters. Density-functional theory exchange-correlation functionals within the generalized gradient or hybrid approximation must be corrected for long-range van der Waals interactions to accurately predict relative gold cluster isomer stabilities. Our paper gives insight into the stable structures of gas phase gold clusters by highlighting the impact of temperature, and therefore the importance of free energy over total-energy studies, and long-range van der Waals interactions on gold cluster stability.
4 More- Received 19 November 2018
- Revised 23 December 2018
DOI:https://doi.org/10.1103/PhysRevMaterials.3.016002
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