@inbook{1eff0de7fadd45929bd7f769059c7c18,

title = "Valence Density Functionals",

abstract = "Since the inception of Density Functional Theory (DFT) the remarkable success of the Local Density Approximation (LDA) has been difficult to improve in a systematic way. Originally Hohenberg, Kohn and Sham introduced LDA as the first term in a gradient expansion of the exchange-correlation energy functional[1]. It success in a wide variety of systems, such as atoms molecules and solids[2, 3], was somewhat surprising, since the density gradients are not small. The accuracy of LDA was attributed to the sum rules which it satisfies[4] and to the range of validity of the small gradient approximation being larger than expected[5, 6]. Well defined gradient expansions[7] were carried out, however the most accurate numerical results for real systems require either a semi-empirical approach[8] or a detailed model for the exchange-correlation hole[9]. A large number of exact constraints have also been placed upon the possible functionals which are beginning to lead to more systematic improvements[10].",

author = "JF Annett",

year = "1995",

doi = "10.1007/978-1-4757-9975-0_20",

language = "English",

isbn = "9781475799774",

series = "NATO Science Series B: Physics",

publisher = "Springer US",

pages = "513--523",

editor = "Gross, {Eberhard K U} and Dreizler, {Reiner M}",

booktitle = "Density Functional Theory",

address = "United States",

}