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We demonstrate the capabilities of time-dependent density functional theory (TDDFT) for strong-field, short wavelength (soft X-ray) physics, as compared to a formalism based on rate equations. We find that TDDFT provides a very good…

We propose a nonadiabatic time-dependent spin-density functional theory (TDSDFT) approach for studying the single-electron excited states and the ultrafast response of systems with strong electron correlations. The correlations are…

Strongly Correlated Electrons · Physics 2013-11-27 Volodymyr Turkowski , Talat S. Rahman

To examine the applicability of the time-dependent density-functional theory (TDDFT) for treating the electron-nucleus coupling in excited states, we calculate the strength distribution associated with the pi-pi* transition in ethylene. The…

Chemical Physics · Physics 2007-05-23 G. F. Bertsch , J. Giansiracusa , K. Yabana

Time-dependent (TD) density functional theory (TDDFT) promises a numerically tractable account of many-body electron dynamics provided good simple approximations are developed for the exchange-correlation (XC) potential functional (XCPF).…

Other Condensed Matter · Physics 2008-08-29 Roi Baer

Energy transfer processes from a high-intensity ultrashort laser pulse to electrons in simple dielectrics, silicon, diamond, and $\alpha$-quartz are theoretically investigated by first-principles calculations based on time-dependent density…

Optics · Physics 2019-05-22 Atsushi Yamada , Kazuhiro Yabana

We formulate a time-dependent density functional theory (TDDFT) 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…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 V. Turkowski , C. A. Ullrich

Experimental observations of the ultrafast (less than 50 fs) demagnetization of Ni have so far defied theoretical explanations particularly since its spin-flipping time is much less than that resulting from spin-orbit and electron-lattice…

Strongly Correlated Electrons · Physics 2020-07-08 Shree Ram Acharya , Volodymyr Turkowski , Guo-ping Zhang Talat S. Rahman

An approximate method based on adiabatic time dependent density functional theory (TDDFT) is presented, that allows for the description of the electron dynamics in nanoscale junctions under arbitrary time dependent external potentials. In…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Y. Wang , C. -Y. Yam , G. H. Chen , Th. Frauenheim , T. A. Niehaus

A practical computational scheme based on time-dependent density functional theory (TDDFT) and ultrasoft pseudopotential (USPP) is developed to study electron dynamics in real time. A modified Crank-Nicolson time-stepping algorithm is…

Materials Science · Physics 2007-05-23 Xiaofeng Qian , Ju Li , Xi Lin , Sidney Yip

We propose a computationally efficient approach to the nonadiabatic time-dependent density functional theory (TDDFT) which is based on a representation of the frequency-dependent exchange correlation kernel as a response of a set of damped…

Mesoscale and Nanoscale Physics · Physics 2019-12-18 Dmitry R. Gulevich , Yaroslav V. Zhumagulov , Alexei V. Vagov , Vasili Perebeinos

This chapter provides a basic introduction to excited-state extensions of density functional theory (DFT), including time-dependent (TD-)DFT in both its linear-response and its explicitly time-dependent formulations. As applied to the…

Chemical Physics · Physics 2023-05-02 John M. Herbert

We investigate the time an electronic excitation travels in a supermolecular setup using a measurement process in an open quantum-system framework. The approach is based on the stochastic Schr\"odinger equation and uses a Hamiltonian from…

Materials Science · Physics 2013-12-09 Dirk Hofmann , Heiko Appel , Massimiliano Di Ventra , Stephan Kümmel

Due to the strongly nonlocal nature of $f_{xc}({\bf r},{\bf r}',\omega)$ the {\em scalar} exchange and correlation (xc) kernel of the time-dependent density-functional theory (TDDFT), the formula for Q the friction coefficient of an…

Materials Science · Physics 2009-11-13 V. U. Nazarov , J. M. Pitarke , Y. Takada , G. Vignale , Y. -C. Chang

Time-dependent density-functional theory (TDDFT) treats dynamical exchange and correlation (xc) via a single-particle potential, Vxc(r,t), defined as a nonlocal functional of the density n(r',t'). The popular adiabatic local-density…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. A. Ullrich , I. V. Tokatly

We develop a generalization of the Kohn-Sham density functional theory (KS-DFT) + Hubbard $U$ (DFT+$U$) method to the excited-state regime. This has the form of Hubbard $U$ corrected linear-response time-dependent DFT, or `TDDFT+$U$'.…

Strongly Correlated Electrons · Physics 2019-04-24 Okan K. Orhan , David D. O'Regan

The ultra-fast demagnetization of small iron clusters initiated by an intense optical excitation is studied with time-dependent spin density functional theory (TDSDFT). In particular we investigate the effect of the spin-orbit interaction…

Mesoscale and Nanoscale Physics · Physics 2016-07-27 Maria Stamenova , Jacopo Simoni , Stefano Sanvito

Most applications of time-dependent density-functional theory (TDDFT) use the adiabatic local-density approximation (ALDA) for the dynamical exchange-correlation potential Vxc(r,t). An exact (i.e., nonadiabatic) extension of the…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 C. A. Ullrich

We theoretically investigate the optically-induced demagnetization of ferromagnetic FePt using the time-dependent density functional theory (TDDFT). We compare the demagnetization mechanism in the perturbative and nonperturbative limits of…

Materials Science · Physics 2024-04-26 M. S. Mrudul , Peter M. Oppeneer

We present a new methodology for the linear-response time-dependent density functional theory (LR-TDDFT) calculation of the dynamic density response function of warm dense matter in an adiabatic approximation that can be used with any…

Computational Physics · Physics 2023-05-12 Zhandos A. Moldabekov , Michele Pavanello , Maximilian P. Boehme , Jan Vorberger , Tobias Dornheim

We analyze possible ways to calculate magnetic exchange interactions within the density functional theory plus dynamical mean-field theory (DFT+DMFT) approach in the paramagnetic phase. Using the susceptibilities obtained within the ladder…

Strongly Correlated Electrons · Physics 2023-06-09 A. A. Katanin , A. S. Belozerov , A. I. Lichtenstein , M. I. Katsnelson
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