Theoretical studies on magnetic interaction in one-dimensional spin chains of hydrogen atoms (H_n) and copper bromide (Cu_nBr_m)

Theoretical calculations of ab initio molecular orbital and density functional theory calculations were carried out in order to investigate magnetic interaction in one-dimensional spin chains. Effective exchange integral (J_ab) values are useful parameters in studying magnetic interaction in spin systems. Chemical indices also were evaluated to represent stability of broken symmetry spin. For one set of spin chains, alignment of hydrogen atoms as the most simple organic cluster was employed. Number of H atoms in employed models is two and 50 with interatomic distance 2.1 Å. In addition, copper bromide chains (Cu_nBr_m) were also studied. Simple molecules Br₂-Cu-Br₂-Cu-Br₂ (without apical-Br) and Br₂-CuBr-Br₂-CuBr-Br₂ (with apical-Br) were employed for simple model structure. Four parameters (r, a, b, and c) can fix the structure and study parameter dependency of J_ab values. For experimental studies, Sugimoto and his coworkers have reported synthesis and experimental studies for complex of both Cu_nBr_m chains and TTF-derivative donor. Magnetic behavior in only Cu_nBr_m chains was investigated in detail by several ab initio methods. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004