Université de Montréal - Pavillon Roger-Gaudry
Ongoing developments in BigDFT towards the ab-initio computation of resonant states
Alessandro Cerioni, Laboratoire L_Sim du CEA de Grenoble, France
Wavefunctions obtained through Density Functional Theory (DFT) are customarily used as a starting point for many-body perturbation theory computations based on one-particle Green's functions as well as in Casida's approach to linear response. Obtaining a reliable description of unoccupied electronic states in finite systems (atoms, molecules, clusters) is quite a challenge, as the density of states is not homogeneous across any given energy range and it depends on the simulation box size in an inconvenient way. Yet, electronic excited states in a given energy interval can be described by few (discrete) resonant states instead of many (in principle infinite) continuum states. Work is in progress toward enabling the computation of such resonant states in the BigDFT code, a high-performance open-source implementation of DFT in real-space adopting Daubechies wavelets as basis set. In my presentation, I will give an overview of present capabilities of BigDFT, introduce the complex scaling method and, finally, discuss a couple of methods for the iterative extraction of resonant states.
Cette conférence est présentée par le RQMP Versant Nord du Département de physique de l'Université de Montréal et le Département de génie physique de Polytechnique Montréal.