Transferability of energies of atoms in organic molecules

The variation of virial-corrected energies of atoms in organic molecules (AIMs) with the lengths of the attached alkyl chains and the nature of remote substituents is shown to be largely an artifact of the correction procedure itself. Thus, it is demonstrated that the virial correction for energies of AIMs should be avoided despite the fact that it produces values that sum up to the total molecular energies. Consequently, the assessment of transferability of AIMs should be carried out with either uncorrected total energies (i.e., negative kinetic energies) or atomic properties other than energy.