The dissociation energy of a spherical ion pair at zero kelvin

8 The dissociation energy of a spherical ion pair at zero kelvin 

Since we have chosen to define the energy as zero for the separated neutral atoms, 

Introduction of the zero point vibrational energy Eq yields the dissociation energy at 0 K  

Insertion of the ionization energy of one metal atom, the electron affinity of one halogen atom and the zero point energy of one molecule yields the dissociation energy of one MX molecule. Alternatively insertion of the ionization energy and electron affinity per mole atoms and multiplication of the last two terms by the Avogadro number yield the dissociation energy per mole MX(g)  

The dissociation energies calculated from equations (5.16) or (5.16a) depend on the value chosen for the exponent , but the reader may convince herself that a change of n from 10 to 12 has little effect. 

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