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用从头计算方法研究了B_(12)C_xN_(12-x)(x=2,4)笼的几何和电子结构.从B_(12)N_(12)中用C原子替换N原子得到B_(12)C_xN_(12-x),这样取代的结构中只含B—C和B—N键.在稳定结构中,C原子在四元环上,形成了B_2C_2和B_2N_2环.B_(12)C_2N_(10)的HOMO主要由C和N的2p轨道组成,LUMO位于-3.6eV处,主要由C的2p轨道组成.B_(12)C_4N_8的HOMO也主要由C和N的2p轨道组成,LUMO位于-4.1eV处,主要由C的2p轨道组成.在B_(12)N_(12),B_(12)C_2N_(10)和B_(12)C_4N_8中B原子上的电荷约为1.17e,C原子上的电荷为-0.75e.B_(12)N_(12),B_(12)C_2N_(10)和B_(12)C_4N_8的能带隙分别为6.84eV,3.50eV和2.82eV.
The geometrical and electronic structures of B 12 C x N 12-x (x = 2, 4) cages were studied by ab initio method. The B atoms were replaced by C atoms from B 12 N 12, ) C_xN_ (12-x), and the substituted structure contains only B-C and B-N bonds. In the stable structure, C atoms form B_2C_2 and B_2N_2 rings on the four- 10) consists mainly of 2p orbitals of C and N. LUMO is located at -3.6eV and is mainly composed of 2p orbitals of C. The HOMO of B_ (12) C_4N_8 is also mainly composed of 2p orbitals of C and N with LUMO at - At 4.1 eV, it mainly consists of 2p orbitals of C. The charge on the B atom in B 12 N 12, B 12 C 2 N 10 and B 12 C 4 N 8 is about 1.17e, (12) N 12, B 12 C 2 N 10 and B 12 C 4 N 8 are 6.84eV, 3.50eV and 2.82eV, respectively.