Structures and stability of lithium monosilicide clusters SiLin (n = 4–16): What is the maximum number, magic number, and core number for lithium coordination to silicon?
✍ Scribed by Ning He; Hong-Bin Xie; Yi-Hong Ding
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 858 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
Abstract
In the coordination, hypervalent and cluster chemistry, three important characteristic properties are the maximum coordination number, magic number, and core coordination number. Yet, few studies have considered these three numbers at the same time for an ML__~n~__ cluster with n larger than 8. In this article, we systematically studied the three properties of SiLi__~n~__ (n = 4–16) clusters at the B3LYP/6‐31G(d), B3LYP/6‐311++G(2d), and CCSD(T)/6‐311++G(3df)//B3LYP/6‐311++G(2d) (for energy only) levels. Various isomeric forms with different symmetries were calculated. For each SiLi__~n~__ (n = 4–9), silicon cohesive energy (cE) from SiLi__~n~__ → Si + Li__~n~__ reaction, vertical ionization potential (vIP), and vertical electron affinity (vEA) were obtained for the lowest‐energy isomer. We found that the maximum Li‐coordination number of Si is 9, which is the largest number among the known MLi__~n~__ clusters. All cE, vIP, and vEA values predicted that 6 is the magic Li‐coordination number of Si. For small SiLi__~n~__ (n ≤ 6) clusters, Li atoms favor direct coordination to Si, whereas for larger SiLi__~n~__ (n ≥ 7) clusters, there is a core cluster that is surrounded by excessive Li atoms. The core Li‐coordination number is 6 for SiLi__~n~__ (n = 7,8), 7 for SiLi__~n~__ (n = 9,10), 8 for SiLi__~n~__ (n = 11–15) and 9 for SiLi__~n~__ (n ≥ 16). Through the calculations, we verified the relationship between the structure and stability of SiLi__~n~__ with the maximum coordination number, magic number, and core coordination number. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008