By comparing the computed energy and available experimental result,we find that the B3LYP,B3P86 and CBS-Q methods are unable to give a good result of bond dissociation energy,however,the.

The electrostatic effect constants for the substituents in an aromatic system were used firstly to study the bond dissociation enthalpy (BDE) of a halomethane system Y-CHnX3-n (n=0,1,2 and 3; Y=H,F,Cl,Br and I; X=F,Cl,Br and I).

Through estimating the activation energy values of elementary reactions by the bond dissociation energy of the reaction system, it is calculated that 2, 6-dichloropyridine is the major product in the photochemical chlorination of 2-chloropyridine, which is consistent to the results of the experiment.

The bond dissociation energy(BDE) for removal of the NO_2 group from the benzene ring and from the alkyl were calculated for the two class molecules employing B3LYP method of Density Functional Theory with the 6-31G~* basis set.

The bond dissociation energy(BDE) for removal of the NO2 group from the benzene ring and from the alkyl were calculated for the four molecules employing the B3LYP-6-31G*、B3P86/6-31G* and B3LYP-6-311G* methods of Density Functional Theory,respectively.

The bond dissociation energy(BDE) is a basic factor which can influence the chemical activity and is an import factor in the course of the free group.

The C-N bond dissociation energies,averaged C-N bond dissociation energies and averag nitryl binding energies of fourteen kinds of [60] polynitrofullerenes were calculated with the PBE density functional theory method.