Dresden 2011 – scientific programme

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O: Fachverband Oberflächenphysik

O 2: Focussed session: Theory and computation of electronic structure: new frontiers I (jointly with HL, DS)

O 2.6: Talk

Monday, March 14, 2011, 12:45–13:00, TRE Phy

One dimensional model systems in time-dependent density functional theory — •Nicole Helbig¹, Johanna I. Fuks¹, Ilya V. Tokatly^1,2, and Angel Rubio^1,3 — ¹ETSF Scientific Development Centre and Universidad del País Vasco, San Sebastián, Spain — ²IKERBASQUE, Basque Foundation for Science, Bilbao, Spain — ³Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin, Germany

We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte-Carlo calculations. Results for the ground-state energies and ionization potentials of finite 1D systems show excellent agreement with exact calculations, obtained by exploiting the mapping of an N-electron system in d dimensions, onto a single electron in N× d dimensions properly symmetrized by the Young diagrams. We conclude that 1D LDA is of the same quality as its three-dimensional (3D) counterpart, and we infer conclusions about 3D LDA. The linear and non-linear time-dependent responses of 1D model systems using LDA, exact exchange, and the exact solution are investigated and show very good agreement in both cases, except for the well known problem of missing double excitations. Consequently, the 3D LDA is expected to be of good quality beyond linear response. We employ the 1D LDA and exact exchange functionals to investigate the description of Rabi oscillations in time-dependent density functional theory and show that adiabatic approximations to the exchange-correlation potential lead to detuned Rabi oscillations.