This can lead to predictions of experimental quantities such as the low-temperature electronic specific heat as well as the spin susceptibility. The Hartree-Fock method is concerned with calculating the many-body wavefunction and the ground state energies by including the effects of electron-electron interactions. It is based on the assumption that the electrons in a many electron atom feel a constant potential over their wavelength and, thus, may be approximated by a local plane wave. the ionization energy and the polarizability.

Therefore, with a shorter wavelength, it would be difficult to define a 'screening cloud' as the perturbation would be varying inside the 'cloud'.Дў) As for the difference between the Thomas-Fermi method and the Hartree-Fock method, the simplest answer is that they seek to calculate different quantities. Thomas and Fermi and allows for the calculation of some simple properties of many electron atoms and ions, e.g. rac_F$).ДЄs the wavelength of the perturbation gets shorter and shorter, the perturbation would start to 'see' more of the graininess in the electron gas/liquid. The former condition corresponds, in a real experiment, to keeping the metal/fluid in electrical contact with a fixed potential difference with ground. A quantification of the screening is the inverse dielectric function of the material: In the Fermi-Thomas approximation,4named after Llewellyn Thomas and Enrico Fermi, the system is maintained at a constant electron chemical potential (Fermi level) and at low temperature. 1) The Thomas-Fermi method is a useful way to estimate the 'screening cloud' surrounding electrons in a metal.

Thomas fermi screening constant