The Experiential Modification of Mullikens Overlap Population as the Judgment of Bond Strength

We modified Mulikens overlap population n(A, B)=2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ and obtained an experiential formula N(A,B)=N_A(A,B)+N_B(A,B) of judging bond strength, where N_A(A, B)=\{Z_AN~2_A(2∑Bλ∑Aμ∑i\}n_ic~*_A,μic_B,λis_Aμ,Bλ), N_B(A, B)=Z_BN~2_B(2∑Bλ∑Aμ∑in_ic~*_A,μic_B,λis_Aμ,Bλ). Twenty-eight bonds calculated by IEHM method and 11 monohydrides calculated by using 6-31G~** basis sets at Hartree-Fock level, electronic correlation effects are also considered through MP2/6-31G~**, were used to verify our experiential formula. Compared with the judgment of chemical bond strength by means of Mulikens overlap population, our experiential formula has a more obvious improvement as a judgment of bond strength than Mulikens overlap population. As a judgment of chemical bond strength between atoms in molecules, the experiential formula has conquered some limitations of Mulikens overlap population, and accorded with the experimental results.