Theoretical studies on electronic structures and magnetic interactions of K 4[Pt 2(pop) 4X] · 2H 2O (X = Cl, Br) complexes

Abstract

Electronic structures, CDW/CP stability and magnetic properties of K 4[Pt 2(pop) 4X] · 2H 2O (X = Cl, Br) complexes are examined by unrestricted DFT (UB3LYP) method. The calculated energies indicate that the CDW is a ground state, and energy differences between CDW and CP structures ( Δ CP–CDW) are 0.34 eV and 0.23 eV for Cl and Br complexes, respectively, within the calculated models. Magnetic interactions between Pt 2 5 + units in the CP structure are also calculated. Calculated intra-chain exchange coupling constants ( J) are −889 cm −1 and −1537 cm −1 for Cl and Br complexes, respectively, indicating a strong anti-ferromagnetic interaction. On the other hand, calculated inter-chain J values suggest a negligible exchange interaction between two chains. In addition, it is also found that orbitals of potassium ions scarcely affect to Δ CP–CDW and J values.