Negative ions of molecules

The simple rigid dipole theory is not truly applicable to a molecule, because the polarisation is altered by the presence of the additional electron, i.e. we have a combination of the two mechanisms. Jordan and Luken [76] have set up a more elaborate ab initio model using a Hartree-Fock scheme, which accounts satisfactorily for molecular relaxation. 

In the spirit of section 1.15, since LiC is a closed shell molecule, the bonding of an extra electron to it might seem surprising at first sight. The fact that the mechanism involved is due to the presence of a dipole moment shows how cautious one must be in applying united atom models too literally to molecules. 

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