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Size‐Dependent Binding Energies of Methane to Small Gold Clusters
Author(s) -
Lang Sandra M.,
Bernhardt Thorsten M.,
Barnett Robert N.,
Landman Uzi
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900844
Subject(s) - chemistry , binding energy , cluster (spacecraft) , density functional theory , methane , atomic orbital , transition state theory , transition state , cluster size , molecular orbital , thermodynamics , reaction rate constant , kinetics , computational chemistry , chemical physics , atomic physics , molecule , electronic structure , physics , catalysis , biochemistry , organic chemistry , quantum mechanics , computer science , programming language , electron
The reactions of small gold cluster cations Au x + ( x =2–6) with CH 4 were studied by joint gas‐phase kinetics and first‐principles density functional theory calculations. The experimentally obtained temperature‐dependent low pressure rate constants were analyzed by employing the Lindemann energy transfer model for association reactions in conjunction with statistical RRKM theory. In this way cluster‐size‐dependent binding energies of methane to the gold cluster cations were determined from the experimental data for two different transition‐state models. The experimental binding energies obtained by employing a “loose” transition‐state model are in good agreement with the theoretical values at the optimal adsorption geometries, while a “tight” transition‐state model clearly gives a lower limit for the binding energies. Additionally, Kohn–Sham molecular orbitals of Au x CH 4 + are presented to gain detailed insight into the cluster–methane bonding mechanism.