Towards time-dependent current-density-functional theory in the non-linear regime

Escartín JM, Vincendon M, Romaniello P, Dinh PM, Reinhard PG, Suraud E (2015)

Publication Type: Journal article

Publication year: 2015

Journal

Journal of Chemical Physics AIP Publishing

Book Volume: 142

Article Number: 084118

Journal Issue: 8

DOI: 10.1063/1.4913291

Abstract

Time-Dependent Density-Functional Theory (TDDFT) is a well-established theoretical approach to describe and understand irradiation processes in clusters and molecules. However, within the so-called adiabatic local density approximation (ALDA) to the exchange-correlation (xc) potential, TDDFT can show insufficiencies, particularly in violently dynamical processes. This is because within ALDA the xc potential is instantaneous and is a local functional of the density, which means that this approximation neglects memory effects and long-range effects. A way to go beyond ALDA is to use Time-Dependent Current-Density-Functional Theory (TDCDFT), in which the basic quantity is the current density rather than the density as in TDDFT. This has been shown to offer an adequate account of dissipation in the linear domain when the Vignale-Kohn (VK) functional is used. Here, we go beyond the linear regime and we explore this formulation in the time domain. In this case, the equations become very involved making the computation out of reach; we hence propose an approximation to the VK functional which allows us to calculate the dynamics in real time and at the same time to keep most of the physics described by the VK functional. We apply this formulation to the calculation of the time-dependent dipole moment of Ca, Mg and Na2. Our results show trends similar to what was previously observed in model systems or within linear response. In the non-linear domain, our results show that relaxation times do not decrease with increasing deposited excitation energy, which sets some limitations to the practical use of TDCDFT in such a domain of excitations.

Authors with CRIS profile

Paul-Gerhard Reinhard Naturwissenschaftliche Fakultät

Involved external institutions

Université Fédérale de Toulouse Midi-Pyrénées FR France (FR) Université Toulouse III - Paul Sabatier FR France (FR)

How to cite

APA:

Escartín, J.M., Vincendon, M., Romaniello, P., Dinh, P.M., Reinhard, P.-G., & Suraud, E. (2015). Towards time-dependent current-density-functional theory in the non-linear regime. Journal of Chemical Physics, 142(8). https://doi.org/10.1063/1.4913291

MLA:

Escartín, J. M., et al. "Towards time-dependent current-density-functional theory in the non-linear regime." Journal of Chemical Physics 142.8 (2015).

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