The chemical bond and solid‐state physics

FEB 01, 1970

A new scale of ionicity, with which the ionic character of bonding in crystals can be predicted and measured, has led to improved understanding of such crystalline properties as lattice structure, heats of formation, elastic constants and nonlinear optical properties.

DOI: 10.1063/1.3021959

James C. Phillips

ADVANCES in quantum chemistry, as in any other field, need novel concepts to keep pace with the great increase in available experimental data and theoretical understanding. The concept of ionicity of the chemical bond is an example. For 35 years Linus Pauling’s development of a definition of ionicity, based on heats of formation of binary crystals, was standard. Here I will describe a new definition of ionicity, derived from spectroscopically obtained transition energies between bonding and antibonding states of semiconductor crystals, and show how it compares with the older one.

References

1. L. Pauling, The Nature of the Chemical Bond, Cornell Univ. Press, Ithaca (1960), esp. p. 91ff and p. 221ff.
2. L. Salem, The Molecular Orbital Theory of Conjugated Systems, Benjamin, New York (1966), esp. p. 147.
3. W. A. Harrison, Pseudopotentials it the Theory of Metals, Benjamin, New York (1966).
4. J. C. Phillips, “The Fundamental Optical Spectra of Solids” in Solid State Physics 18, Academic Press, New York (1966).
5. M. L. Cohen, T. K. Bergstresser, Phys. Rev. 141, 789 (1966).https://doi.org/PHRVAO
6. M. Tosi, “Cohesion of Ionic Solids in the Born Model,” in Solid State Physics 16, Academic Press, New York (1964).
7. J. C. Phillips, Phys. Rev. Lett. 20, 550 (1968); https://doi.org/PRLTAO
J. A. Van Vechten, Phys. Rev. (in press).
8. J. C. Phillips, Phys. Rev. Lett. 22, 645 (1969).https://doi.org/PRLTAO

More about the Authors

James C. Phillips. Theoretical‐Physics Department, Bell Labs.