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第一原理计算了BaC2低温和常温两种异构体的电子结构性质,得到了二碳化钡的能带结构及电子密度.发现BaC2是典型的离子键结合晶体,认为在两种异构体中存在强C—C共价键及Ba—C离子键.分析了两种结构的Ba—C间电子密度及布居分布,认为结构中哑铃形的C2为C≡C键,在I4/mmm结构中相互作用的Ba—C2距离为0.2945nm,C2/c为0.2744nm,C≡C键长在两种晶体结构中分别为0.1185nm,0.1136nm,与C2H2中的C≡C键长相似.I4/mmm结构的能带子带拆解表明了原子亚层电子的轨道成键,讨论了C22-的电荷转移及对材料的影响.BaC2两种结构的振动谱和热力学性质计算表明,其异构体结构转变是典型的温度诱发相变,相变温度约为132K,与相关文献的预测一致.
The first principle calculated BaC2 low temperature and room temperature electronic structure of the two isomers of the electronic structure obtained barium bicarbonate band structure and electron density found BaC2 is a typical ion-bonded crystals, that in the two isomers There is a strong C-C covalent bond and Ba-C ionic bond.By analyzing the Ba-C electron density and population distribution of the two structures, it is considered that the dumbbell shaped C2 in the structure is a C≡C bond, and in the I4 / mmm structure The Ba-C2 distance in the interaction is 0.2945nm, the C2 / c is 0.2744nm, and the C≡C bond length is 0.1185nm and 0.1136nm respectively in the two crystal structures, which is similar to the C≡C bond length in C2H2. / mmm structure of the band dismantling of the atomic subatomic electron orbital bonding showed that the C22- charge transfer and the impact on the material.BaC2 two structures vibrational and thermodynamic properties of the calculated results show that the isomers Structural transformation is a typical temperature-induced phase transition, the phase transition temperature is about 132K, consistent with the relevant literature.