Prof. Anthony Dutoi
University of the Pacific, California, Etats-Unis
The presentation will have two parts. The larger first part will be on a new project that is ripe for outside input. The second will be a gloss of my more regular interests, by way of introduction. Part I: The peaks of X-ray photoelectron spectra exhibit some features that have not found satisfactory theoretical explanation. The focus of the present theoretical work is an asymmetry in the fundamental lineshape of some peaks. Conventional field-specific approaches do not withstand experimental and theoretical scrutiny. We have provided interpretation in terms of two (or more) coupled resonance (CR) states, which we further hypothesize to be present due to the spatially asymmetric effect on co-located valence orbitals of transient p-symmetry core holes. However, the interpretation of the lineshape parameters is an area of ongoing work. Part II: A new electronic structure model [excitonic renormalization (XR)] seeks to handle hundreds to thousands of active, explicitly correlated electrons with tunable accuracy. The basis of the model is to use information computed for internally correlated isolated subsystems to write a second-quantized-like supersystem Hamiltonian, to which traditional methods can be applied. A key feature of this ab initio model is its systematic improvability.