B. Craig Taverner & Jan C. A. Boeyens

In 1963 Herman and Skillman[1] produced the well known numerical atomic Hartree-Fock-Slater program to calculate the energies and densities of electron nl orbitals. The orbital energies for the entire periodic table were calculated and published. In 1994 this program was modified to allow for the simulation of the compression of the atoms by the multiplication of all wave functions by a step function at a particular radius, in each cycle of the self consistent field calculation. By squeezing the atoms in this way, the electron densities and orbital energies on compressed could be modeled. The increase in orbital energies can be used to model ionization and bonding phenomena. Compressed wave functions can be used to model electron densities in condensed phases, and therefore be useful in crystallographic studies of electron densities in crystals. Several crystals have been selected for electron density study using scattering factors calculated directly from the compressed atoms. These results are compared to those obtained using published scattering factors[3].

1. F. Herman and S. Skillman, Atomic Structure Calculations, Prentice-Hall, New Jersey, 1963.
2. J. C. A. Boeyens, Ionization Radii of Compressed Atoms, J. Chem. Soc. Faraday Trans., 90(0), 1994
3. International Tables for X-Ray Crystallography, Volume III, The Kynoch Press, Birmingham, 1968.