Abstract:

With density functional theory(DFT)，all 209 possible molecular space structure patterns of polychlorinated diphenyl ethers(PCDEs)were optimized and the frequency was analyzed at the B3LYP/6-31+G(d)level and the topological distance matrix was built with the space topological distance among atoms. A new group of quantum topological indices PX₁ and PX₂ was introduced based on the topological distance matrix，and the branch vertex of atoms in a molecule was put forward by coloring atoms in the molecular graph with equilibrium electro-negativity. The seven QSPR models between thermodynamic properties，Δ_fH ^?，Δ_fG ^?_R   and Δ_fG ^?，and the quantum topological indices PX₁ and