MOLECULAR ELECTRONEGATIVITY IN DENSITY-FUNCTIONAL THEORY .1. DIRECT CALCULATION OF ATOMIC CHARGES IN A MOLECULE VIA ELECTRONEGATIVITY EQUALIZATION PRINCIPLE

On the basis of electronegativity expressed in density functional theo ry and electronegativity equalization principle, a new scheme for calc ulating the atomic charges in a molecule has been proposed and designe d, which gives a new scale of the atomic electronegativity and hardnes s in a certain molecular environment and takes the harmonic mean elect ronegativity as a reference value of the molecular electronegativity s o that the multiple-regression and nonuniform parameters in the origin al method are avoided. This approach on be easily and widely applied t o the calculation of atomic charges for a big molecule and quite good results of atomic charges in some illustrated molecules are obtained a s compared with those From the ab initio STO-3G SCF calculations.