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Planarization of B20 clusters by Si and C atom substitution
Qi Liang Lu1, Qi Quan Luo, Yi De Li
1School of Physics and Material Science, Anhui University, Hefei 230601, Anhui, P. R. China. qllufd@vip.sina.com.
Physical Chemistry Chemical Physics : PCCP
|October 18, 2017
Summary
Substituting silicon (Si) or carbon (C) atoms into boron (B) clusters induces planarization. B19Si and B19C clusters adopt novel planar and quasi-planar structures, respectively, differing from the tubular B20 cluster.
Area of Science:
- Computational Chemistry
- Materials Science
- Quantum Mechanics
Background:
- Boron clusters exhibit diverse structures, including tubular forms like B20.
- Substitution of heavier atoms can significantly alter cluster geometries and properties.
- Understanding structure-property relationships in boron-based materials is crucial.
Purpose of the Study:
- To determine the lowest energy structures of B19Si and B19C clusters.
- To investigate the structural transition from tubular B20 to substituted clusters.
- To explore the electronic properties and bonding characteristics of the new structures.
Main Methods:
- Employed a hybrid optimization strategy combining global semi-empirical quantum mechanical search with all-electron density functional theory (DFT).
- Investigated the stability and electronic properties of B19Si and B19C clusters.
- Analyzed geometric parameters, charge distribution, and frontier molecular orbital gaps (HOMO-LUMO).
Main Results:
- Observed a significant planarization effect upon Si and C substitution in B20.
- Determined distinct lowest energy structures: an almost perfect planar B19Si and a quasi-planar bowl-shaped B19C.
- Identified Si and C atoms occupying peripheral positions, influencing sp2 hybridization and bonding.
Conclusions:
- The substitution of Si and C atoms drives the transition from a tubular to planar/quasi-planar structures in boron clusters.
- The planarization is attributed to a combination of sp2 hybridization, altered peripheral bonding, and mechanical effects.
- The study provides insights into the structural and electronic properties of novel B19Si and B19C clusters.
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