All-electron ab initio calculations of YBa_2Cu_3O_7 with self-consistence crystal field  

作　　者：刘洪霖 陈念贻 

机构地区：[1]Shanghai Institute of Metallurgy,Chinese Academy of Sciences,Shanghai 200050,China

出　　处：《Science China Chemistry》1995年第8期927-933,共7页中国科学（化学英文版）

摘　　要：The quantum chemical calculations of cluster YBa_2Cu_3O_7 considering all electrons have been per- formed by using the ab initio HF method with self-consistence crystal field.A Hartree-Fork surface potential is proposed to make an asymmetric duster model possess a relatively symmetric potential field and to obtain a relatively symmetric electronic structure,electronic distributions,frontier orbitals,and bond order,etc.The suggestions that there exists a covalent bonding complex,[CuO_2-O-CuO-O-Cu_2]^(6,8-),in the cell unit of the crystal,and the cell units are connected with each other by ionic bonds along the c direction of the crys- tal lattice are offered based on the chemical bonding characteristics from the calculated results.The important contribution of the apical oxygen to superconductivities is emphasized as well.The quantum chemical calculations of cluster YBa₂Cu₃O₇ considering all electrons have been per-formed by using the ab initio HF method with self-consistence crystal field.A Hartree-Fork surface potentialis proposed to make an asymmetric duster model possess a relatively symmetric potential field and to obtaina relatively symmetric electronic structure,electronic distributions,frontier orbitals,and bond order,etc.Thesuggestions that there exists a covalent bonding complex,[CuO₂-O-CuO-O-Cu₂]^6,8-,in the cell unit ofthe crystal,and the cell units are connected with each other by ionic bonds along the c direction of the crys-tal lattice are offered based on the chemical bonding characteristics from the calculated results.The importantcontribution of the apical oxygen to superconductivities is emphasized as well.

关 键 词：YBa_2Cu_3O_7 SUPERCONDUCTIVITY quantum chemical calculations 

分 类 号：O611.3[理学—无机化学]