https://doi.org/10.1140/epjd/e2012-20464-3
Regular Article
Theoretical investigation on the structure and electronic properties of bimetallic gold-zinc cluster cations and their monocarbonyls*
1
Institute of Atomic and Molecular Physics, Sichuan
University, Chengdu
610065, P.R.
China
2
International Centre for Materials Physics, Academia
Sinica, Shenyang
110016, P.R.
China
a e-mail: scumaj@126.com
Received:
9
August
2011
Received in final form:
23
December
2011
Published online:
29
March
2012
Using the first principles calculations, the mixed AunZn (n + m ≤ 6) cluster cations and their
monocarbonyls AunZnmCO+
have been investigated at the PW91 level. For the small AunZn
, most ground-state isomers are planar structures. A significant odd-even
oscillation of the highest occupied-lowest unoccupied molecular orbital energy gaps with
the number of Au atoms is observed. Upon CO adsorption, the top site and C head-on
adsorptions are most favorable in energy. Moreover, the optimized geometries indicate that
the CO molecule prefers binding to Au atom of the AunZn
clusters, which can be understood by the frontier molecular orbital
theory in detail. From the theoretical calculations, the CO charge population, CO binding
energy (BE) and the Gibbs free-energy change ΔG generally decrease with
the increase of the Zn content. It is found that the BE is highly related to the electron
transfer between CO and the cluster cations. Furthermore, a linear correlation between
ΔG and the CO BE is found. The red shift in the CO stretching frequency
is sensitive to the cluster size and composition. Our calculation suggests that CO
reactive collision on Au3Zn+ and Au2Zn
may lead to the dissociation of the clusters with a Zn atom loss.
Key words: Molecular Physics and Chemical Physics
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© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2012