8 th Workshop on Time-Dependent Density-Functional Theory : Applications and Prospects (original) (raw)

Time-dependent density-functional theory for molecules and molecular solids

Journal of Molecular Structure-theochem, 2009

Time-dependent density-functional theory (TDDFT) has become a well-established part of the modern theoretical chemist's toolbox for treating electronic excited states. Yet, though applications of TDDFT abound in quantum chemistry, review articles specifically focusing on TDDFT for chemical applications are relatively rare. This article helps to fill the void by first giving a historical review of TDDFT, with emphasis on molecular excitations and aspects of TDDFT which are important for quantum chemical applications, followed by a discussion of some modern evolutions with emphasis on the articles in this volume, and ending with a few thoughts about the future of TDDFT. j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / t h e o c h e m

Fundamentals of Time-Resolved Charge-Transfer in Time-Dependent Density Functional Theory

We show that as an electron transfers between closed-shell molecular fragments at large separation, the exact correlation potential of time-dependent density functional theory gradually develops a step and peak structure in the bonding region. This structure has a density-dependence that is non-local both in space and time, and even the exact ground-state exchange-correlation functional fails to capture it. In the complementary case of charge-transfer between open-shell fragments, an initial step and peak vanish as the charge-transfer state is reached. Lack of these structures in usual approximations leads to inaccurate charge-transfer dynamics. This is dramatically illustrated by the complete lack of Rabi oscillations in the dipole moment under conditions of resonant charge-transfer.

Time-dependent density-functional theory for ultrafast interband excitations

Physical Review B, 2008

We formulate a time-dependent density-functional theory ͑TDDFT͒ in terms of the density matrix to study ultrafast phenomena in semiconductor structures. A system of equations for the density-matrix components, which is equivalent to the time-dependent Kohn-Sham equation, is derived. From this, we obtain a TDDFT version of the semiconductor Bloch equations, where the electronic many-body effects are taken into account, in principle, exactly. As an example, we study the optical response of a three-dimensional two-band insulator to an external short-time pulsed laser field. We show that the optical absorption spectrum acquires excitonic features when the exchange-correlation potential contains a 1 / q 2 Coulomb singularity. A qualitative comparison of the TDDFT optical absorption spectra with the corresponding results obtained within the Hartree-Fock approximation is made.

Excited states dynamics in time-dependent density functional theory

The European Physical Journal D - Atomic, Molecular and Optical Physics, 2004

We present a theoretical description of femtosecond laser induced dynamics of the hydrogen molecule and of singly ionised sodium dimers, based on a real-space, real-time, implementation of time-dependent density functional theory (TDDFT). High harmonic generation, Coulomb explosion and laser induced photo-dissociation are observed. The scheme also describes non-adiabatic effects, such as the appearance of even harmonics for homopolar but isotopically asymmetric dimers, even if the ions were treated classically. This TDDFT-based method is reliable, scalable, and extensible to other phenomena such as photoisomerization, molecular transport and chemical reactivity.

Time-dependent density functional theory for non-adiabatic processes

2005

Abstract. Time-dependent density functional theory (TDDFT) is a general and robust method allowing the study of electron dynamics whether induced by nuclear motion or by external fields. We give a brief overview of the theory and some numerical methods together with recent applications stressing the generality and wide applicability of the method. We also discuss recent attempts to extend the present TDDFT by incorporating memory terms into the exchange correlation potentials. 1.

Time-dependent density functional theory: Past, present, and future

The Journal of Chemical Physics, 2005

Time-dependent density functional theory ͑TDDFT͒ is presently enjoying enormous popularity in quantum chemistry, as a useful tool for extracting electronic excited state energies. This article discusses how TDDFT is much broader in scope, and yields predictions for many more properties. We discuss some of the challenges involved in making accurate predictions for these properties.

Relaxation in Time-Dependent Current-Density-Functional Theory

Physical Review Letters, 2006

We apply the time-dependent current-density functional theory to the study of the relaxation of a closed many-electron system evolving from an non-equilibrium initial state. We show that the self-consistent unitary time evolution generated by the time dependent exchange-correlation vector potential irreversibly drives the system to equilibrium. We also show that the energy dissipated in the Kohn-Sham system is related to the entropy production in the real system. PACS numbers: 71.15.Mb, 03.65.Yz