Title: Density Functional Theory (DFT) and Time Dependent DFT (TDDFT)
Abstract: The chapter is devoted to the study of density functional theory (DFT) which provides an understanding of a wide range of properties from energetics and geometries of molecules to reaction barriers and van der Waals interactions. Starting from the statements of the Hohenberg–Kohn theorem, it develops Kohn–Sham (KS) equations and the linear combination of atomic orbitals ansatz and describes the approach to solve these equations. Different types of exchange–correlation functionals such as LDA, LSDA, GGA, meta-GGA, and hybrid exchange functionals have been discussed. Since the choice of a functional determines the performance of the theory, guidelines for the selection of the right functional for calculations have been given. The limitations, shortcomings, and challenges before DFT, and new developments to address them have been discussed. In the later part of the chapter, the time-dependent density functional theory (TDDFT), which is probably the most promising theory for the treatment of problems of the excited states of molecules, has been given. This also includes topics such as Runge–Gross theorem, derivation of time-dependent KS equations, linear response theory, Casida's matrix formulation of TDDFT, techniques to calculate electronic excitation, and an account of the various approximate exchange–correlation functionals used for TDDFT calculations.
Publication Year: 2016
Publication Date: 2016-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 10
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