含时密度泛函理论.pdf

TDDFT from molecules to solids: the role of long-range interactions Francesco Sottile,1 Fabien Bruneval,1 A. G. Marinopoulos, 1 Louise Dash, 1 Silvana Botti,1 Valerio Olevano,1 Nathalie Vast,1 Angel Rubio,1,2 and Lucia Reining1 1) Laboratoire des Solides Irradi´es, CNRS-CEA, ´ Ecole Polytechnique F–91128 Palaiseau, France 2) Departamento de F´ısica de Materiales, Facultad de Ciencias Qu´ımicas, Universidad del Pais Vasco, Centro Mixto CSIC-UPV/EHU and Donostia International Physics Center. E–20018 San Sebasti´an/Donostia, Basque Country, Spain (Dated: August 1, 2004) Abstract Classical Hartree effects contribute to a substantial degree to the success of time-dependent den- sity functional theory, especially in finite systems. Moreover, exchange-correlation contributions have an asymptotic Coulomb tail similar to the Hartree term, and turn out to be crucial in de- scribing response properties of solids. In this work, we analyze in detail the role of the long-range part of the Coulomb potential in the dielectric response of finite and infinite systems, and elu- cidate its importance in distinguishing between optical and electron energy loss spectra (in the long wavelength limit q → 0). We illustrate numerically and analytically how the imaginary part of the dielectric function and the loss function coincide for finite systems, and how they start to show differences as the distance between objects in an infinite array is decreased (which simulates the formation of a s