Electrons, high-energy spin-polarized

A spin-polarization of s = 6 electrons has been found in an Xof-SW study of a Nii3 cuboctahedron (75) due to a comparable high density of one-electron levels near the cluster Fermi energy. But in another study using this computational approach s = 8 was calculated (76). 

The information obtainable from photoelectron polarization measurements is reviewed, for both atoms and molecules, by Heinzmann and Cherepkov (1996). Even at non-relativistic excitation energy, photoelectrons can be spin-polarized (Fano, 1969). For l / 0 atoms, due to the spin-orbit splitting of the initial atomic and/or the final ionic state, photoelectrons are in most cases highly spin-polarized (up to 100%) when photoexcited with circularly polarized light. Analogous effects occur in molecular photoionization, but systematic studies have only been made for hydrogen halide molecules, HX. The electronic ground state of HX+ is X2n. 

In the Fe- as well as in the Co compounds there is a substantial enhancement of the Kerr intensity at photon energies near the high-energy spin-polarized 4d(5d) electrons and has already been discussed in sections 3.2.2-3.2.4. 

The analytical form for the correlation energy of a uniform electron gas, which is purely dynamical correlation, has been derived in the high and low density limits. For intermediate densities, the correlation energy has been determined to a high precision by quantum Monte Carlo methods (Section 4.16). In order to use these results in DFT calculations, it is desirable to have a suitable analytic interpolation formula, and such formulas have been constructed by Vosko, Wilk and Nusair (VWN) and by Perdew and Wang (PW), and are considered to be accurate fits. The VWN parameterization is given in eq. (6.36), where a slightly different spin-polarization function has been used. 

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