Fundamentos da Teoria do Funcional de Densidade (DFT): Uma Revisão Histórica e Conceitual

Resumo

The Density Functional Theory (DFT) has established itself as one of the most powerful and widely used
approaches in physics and chemistry for studying the electronic structure of complex systems — including
molecules, solids, catalysts, and advanced materials. This article revisits the historical and conceptual
foundations of DFT, tracing its evolution from early electron gas models to the modern formulation based
on the Hohenberg–Kohn theorems and the Kohn–Sham equations. The relationships between classical
chemical concepts such as electronegativity, hardness, and reactivity, and their formal grounding within
the DFT framework, are discussed. The main advances in the development of exchange–correlation
functionals are also presented, from the local Dirac–Slater model to contemporary hybrid functionals.
Finally, the text addresses the intrinsic limitations of the theory, such as the self-interaction problem,
while highlighting its enormous interpretative power and the importance of theoretical knowledge for
the critical analysis of computational results.
Keywords: Density Functional Theory (DFT); electron gas; GGA; LDA; exchange and correlation.