B_4O分子异构化稳定性的理论研究

Theoretical Study on Isomerization Stability of B_4O Molecule

采用CCSD(T)/6-311+G(2df)//B3LYP/6-311+G(d)方法,系统研究了B4O体系各个异构体的结构和能量,以及重要异构体的解离和异构化稳定性.结果表明,单态平面三角形含—BO单元的异构体cB3-BO11能量最低,其次是带状的异构体B4O12(10.9 kJ/mol),并且11和12结构都具有良好的动力学稳定性.因此对于B4O体系,11和12都是有可能存在的.而文献报道的三态直线型结构BBBBO(146.0 kJ/mol)的能量比异构体11和12高得多.

The recent theoretical studies on the B4O molecule had reported two completely different ground state structures,i.e.,a triplet linear structure BBBBO and a singlet triangle structure with an exocylic-BO moiety-c-B3-BO.In this article,using CCSD（T）/6-311＋G（2df）//B3LYP/6-311＋G（d） method,we systematically investigated the structures and energetics of various B4O isomers as well as the dissociation and isomerization stability of important species.It was shown that the singlet planar triangle structure containing the-BO unit 11 has the lowest energy,followed by the belt-like B4O isomer 12（10.9 kJ/mol）.Both 11 and 12 possess good kinetic stability,and thus might have potential for existence.However,the previously reported triplet linear isomer BBBBO（146.0 kJ/mol） lies energetically much higher than the isomers 11 and 12.The detailed results for B4O reported in this work should provide important information for the growing mechanism of boron oxide clusters as well as the oxidation and doping mechanism of B4 clusters.