Gunnarsson-Lundqvist

The correlation energy can also be found from an approximate self-energy. An early example of this approach was the Gunnarsson-Lundqvist (GL) [41] parametrization, which shows larger deviations (up to 10 millihartree) from PW92 in Tables I and II. Recent and more sophisticated examples [43,44] agree within 2 millihartree with PW92. 

There are a number of model exchange-correlation functionals for the ground-state. How do they perform for ensemble states Recently, several local density functional approximations have been tested [24]. The Gunnarsson-Lundqvist-Wilkins (GLW) [26], the von Barth-Hedin (VBH)[25] and Ceperley-Alder [27] local density approximations parametrized by Perdew and Zunger [28] and Vosko, Wilk and Nusair (VWN) [29] are applied to calculate the first excitation energies of atoms. 

We can see from Table 1 that the Gunnarsson - Lundqvist potential gives the best result comparing with reference data. This is iti contrast with the expectations, because GGA potentials resulted better agreement with experimental data in DFT calculations for several atoms [10). ... 

This approach typically reduced the correlation energy errors for atoms to the 10% range using the Gunnarsson-Lundqvist correlation potential which, unfortunately, is not the most accurate . 

Harris and Jones performed central-field LSD calculations for the 3d and 4d atoms using the Gunnarsson-Lundqvist potential. Their results for... 

N is again the number of valence electrons and the factor of 2 accounts for the spin degeneracy. If the Gunnarsson-Lundqvist parameterization for the exchange and correlation potential is used [22], the effective potential Veff is given (in Rydberg atomic units) by... 

Gunnarsson O and B I Lundqvist 1976. Exchange and Correlation in Atoms, Molecules, and Solids by the Spin-density-functional Formalism. Physical Review B13.-4274-4298. 

The approach that we take to the question of how local and semilocal density functionals work for systems with large density gradients was pioneered by Gunnarsson, Jonson, and Lundqvist [41,42]. Define u = r — r, the separation of two points in the system. Then the spherically-averaged hole is... 

Gunnarsson O, Jonson M, Lundqvist BI (1977) Solid State Commun 24 765... 

O. Gunnarsson and B. I. Lundqvist, Exchange and correlation in atoms, molecules and solids by the spin-density-functional formahsm. Phys. Rev. B 13, 4274-A298 (1976). 

In a more general setting the recipe [91] can be considered as an implementation of another suggestion by Gunnarsson and Lundqvist [99] and von Barth [100] known also at a pretty early stage of the development of the DFT technique of employing different functionals to describe different spin or symmetry states. In other words the simplified model for the data fit Eq.(lO) changes to ... 

B.I. Lundqvist, H. Hjelmberg, and O. Gunnarsson Adsorbate-Induced Electronic States in Photoemission and the Electronic Properties of Surfaces, Eds. B. Feuerbacher, B. Fitton, and R.F. Willis (Wiley, New York, 1978). 

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