The R-i-H bond can be treated as the combination of alkyl radical R; with hydrogen atom H. The bond dissociation energy (BDE) of R-i-H was related to the HOMO energy level of alkyl radical and the atom orbital energy of hydrogen atom. The results showed that a good linear correlation was found between the BDE of R-i-H and the polarizability effect index (PEI) of alkyl radical R: BDE = c + dPEI(R;) . The expression has good precision for evaluating the BDEs of C-H bonds. Moreover, the PEI of alkyl radical R,- can be corelated quantitatively with the reaction rates of alkane with hydroxyl radicals.

Key words: ALKANE, POLARIZATION, APPLICATION, REACTION RATE CONSTANT