van der Waals forces from scattering functions. The Ne--Ne potential
Previous work relating the long-range interaction energy to scattering functions, via the charge-density susceptibility, is extended to two interacting Ne atoms. It is shown that, within the closure approximation, the second order dispersion and polarization energies can be formulated in terms of generalized scattering functions, which for uncorrelated (e.g., Hartree--Fock) atomic functions can be expressed rigorously in terms of ''orbital'' form factors which are the Fourier transforms of the one-electron densities. We calculate the dispersion and polarization energies, using a distance-dependent mean excitation energy, which we evaluate with the aid of overlap integrals, and known values of the collision diameter and atomic polarizabilities. We obtain the total potential energy curve in two ways: (1) by adding the first order Coulomb and exchange energies to the second order dispersion and polarization energies, and (2) by adding the diatom SCF interaction energies to the dispersion energies. The potential curves so obtained are in very good agreement with previous experimental and theoretical values.
- Research Organization:
- Department of Chemistry, The Florida State University, Tallahassee, Florida 32306
- OSTI ID:
- 5885393
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 79:1
- Country of Publication:
- United States
- Language:
- English
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