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Density Functional Study of Physical and Chemical Properties of Nano Size Boron Clusters: Bn (n=13~20)
urat Atis1, Cem Ozdogan*2, Ziya B. Guvenc3
1.Department of Physics, University of Nev?ehir, 50300 Nev?ehir, Turkey;2.Department of Computer Engineering, ?ankaya University, Balgat 06530 Ankara, Turkey;3.Department of Electronic and Communication Engineering, ?ankaya University, Balgat 06530 Ankara,Turkey
Abstract:
Boron is an element that has ability to build strong and highly directional bonds with boron itself. As a result, boron atoms form diverse structural motifs, ultimately can yield distinct nano structures, such as planar, quasi-planar, convex, cage, open-cage, tubular, spherical, ring, dome-like, shell, capsule, and so on, i.e., it can take almost any shape. Therefore, a deep understanding of the physical and chemical properties becomes important in boron cluster chemistry. Electronic and geometric structures, total and binding energies, harmonic frequencies, point symmetries, charge distributions, dipole moments, chemical bondings and the highest occupied molecular orbital-owest unoccupied molecular orbital energy gaps of neutral Bn (n=13~20) clusters have been investigated by density functional theory (DFT),B3LYP with 6-311++G(d,p) basis set. Furthermore, the first and the second energy differences are used to obtain the most stable sizes. We have observed that almost all physical properties are size dependent, and double-ring tubular form of B20 has the highest binding energy per atom. The icosahedral structure with an inside atom is found as impossible as a stable structure for the size thirteen. This structure transforms to an open-cage form. The structural transition from two-dimensional to three-dimensional is found at the size of 20 and consistent with the literature. The calculated charges by the Mulliken analysis show that there is a symmetry pattern with respect to the x-z and y-z planes for the charge distributions. The unusual planar stability of the boron clusters may be explained by the delocalized Π and α bonding characteristic together with the existence of the multicentered bonding. The results have been compared to available studies in the literature.
Key words:  Cluster, Boron, Density functional theory
FundProject:
Density Functional Study of Physical and Chemical Properties of Nano Size Boron Clusters: Bn (n=13~20)
Murat Atis1, Cem Ozdogan*2, Ziya B. Guvenc3
1.内夫谢希尔大学物理系,50300 内夫谢希尔;2.Cankaya大学计算机工程系,Balgat 06530,安卡拉;3.Cankaya大学电子与通讯工程系,Balgat 06530,安卡拉
摘要:
采用密度泛函理论B3LYP与6-311++G方法研究了硼簇Bn(n=13~20)的电子和几何结构、总能量、结合能、谐波频率、点对称性、电荷分布、偶极矩、化学键以及最高分子占据轨道和最低分子占轨道能量差.此外,借助第一和第二能级差确定最稳定的硼簇尺寸.研究表明硼簇几乎所有的物理性质有尺寸依赖性,双环管状结构的B20具有最高平均结合能.内有一原子的二十面体结构的B13不具有稳定构型,这种结构转变为开放式笼状.B20出现二维到三维的结构转变.Mulliken分析表明电荷分布有x-z和y-z平面对称.硼簇的平面稳定性可以通过离域键(π键和α键)以及多中心键来解释.
关键词:  密度泛函理论,团簇,硼
DOI:10.1088/1674-0068/22/04/380-388
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