Modification of the Bornmdash;Mayer Potential Function as Applied to the Crystalline Alkali Halides

摘要

The repulsion constant rgr; in the Bornmdash;Mayer potential function is assigned values which are different for likehyphen; and unlikehyphen;ion pairs in such a way that large deviations from the observed compressibilities of the lithium halides, attributable to marked anionmdash;anion repulsion, are removed. Lattice parameters in excellent agreement with the experimental ones are than obtained using alternative sets of ``basic radii'' based on differently evaluated ionic radii, but an indeterminacy characteristic of the Bornmdash;Mayer equation is shown to affect markedly the calculated likehyphen;ion overlaphyphen;repulsive contributions. The possibility of considerable error in the calculated results through lack of correction for ion asymmetry is discussed. The calculated electron affinities, which are unaffected by these uncertainties, agree approximately with the most precise determinations by other methods.