A Systematic Study of
Structures, Stability, and Electronic Properties of alloy clusters
AlBen (n = 1–12): Comparison with Pure
Beryllium Clusters
Dan Yu, 11Institute of Theoretical Chemistry,
Jilin University, Changchun 130023, (P. R. China)Wei-Ming Sun, 22The
School of Pharmacy, Fujian Medical University, Fuzhou 350108, (P. R.
China) Jing-Yao Liu,1 Di
Wu,1 Ying Li,1 and Zhi-Ru
Li1
Correspondence to: Wei-Ming Sun (E-mail:sunwm@fjmu.edu.cn); Ying
Li (E-mail: liyingedu@jlu.edu.cn )
Introduction
As a bridge between atoms and macroscopic state, cluster science
continues to be a subject of increasing research interest. In the realm
of cluster investigations, metal clusters[1–7]have attracted extensive attention in the last several decades because
they exhibit many intriguing properties that are neither atomic-like nor
extended solidlike,[8,9] while being closely
connected to size, geometry, and composition. These size-dependent
properties offer exciting possibilities for developing finely tuned
cluster-assembled materials, which have promising applications in the
fields of material science, optics, nanotechnology, catalysis,
etc.[10–14]Besides, it has long been recognized that the properties of metal
clusters, instead of evolving linearly with size, usually vary
discontinuously with the number of component
atoms.[11] In this respect, a simple yet helpful
free-electron model, namely spherical jellium model
(SJM),[15] has been
proposed to account for the evolution of properties (even structures) of
numerous pure and doped metal clusters.[16,17]
The fact that beryllium dimer is weakly
bound[18–22] whereas bulk beryllium is a hard
metal with rather high melting point and enthalpy of
atomization[23] makes beryllium cluster an ideal
prototype for exploring the evolution from discrete molecules to
metallic state, as indicated in an overview on the studies of beryllium
clusters.[24] In contrast to experimental studies
which are limited by the toxicity of beryllium, quantum chemistry
provides powerful computational methods that help to investigate
beryllium clusters in detail. By using density functional theory with
Becke–Lee–Yang–Parr gradient correction, Wang et
al.[25] studied the structural and electronic
properties of beryllium clusters containing up to 21 atoms, and they
found that the Be4, Be10 and
Be17 clusters show particularly high stability. With the
help of a modified genetic algorithm, Khanna and
coworkers[26] have revealed the dependence of
relative stability and electronic properties of the
Ben (n = 2 − 41) clusters on their
equilibrium geometries.
Recently, doped metal clusters have attracted much attention from both
theoretical and experimental researchers. It has been found that the
characteristics of pure metal clusters, such as relative stability,
structural evolution, bonding character, electronic and magnetic
properties, etc., are usually altered when a heteroatom is introduced.
Consequently, doped clusters may show new physicochemical properties not
found in pure clusters. In this study, we focus on doped beryllium
clusters and choose Al atom as the dopant atom. On the one hand,
impurity-atom doping may provide additional flexibility to modulate the
physical and chemical properties of beryllium clusters.
On
the other hand, the systematical study of beryllium-aluminum binary
clusters is a meaningful project in view of the important applications
of Be-Al alloys in disk drive armatures, automotive braking systems, and
aerospace and satellite system components.[27-30]
In the present work, we have performed a comprehensive study of the
bimetallic AlBen (n = 1–12)
clusters.
Besides exploring the ground state structures, we also aim to reveal the
evolution of structures, stability, and various electronic structure
related properties of AlBen along with cluster
size. Furthermore, we make a comparison between
AlBen and pure Ben +1clusters from all aspects to analyze the Al-substitution effect. We hope
that results from this study will not only offer a fundamental
understanding of structure-property relationship of subnano-scale
beryllium-aluminum clusters, but provide useful references for studies
of other binary metal clusters.