TIFR
Department of Chemical Sciences
School of Natural Sciences

March 21, 2018 at 2.30 pm in AG-80

Title :

Variational Random Phase Approximation Method for Accurate Ionization Potentials and Interaction Energies

Abstract :

A critical and outstanding challenge of electronic structure method development is to deliver both accurate total energy differences and quasiparticle spectra. I will address this challenge using a generalized Kohn-Sham (GKS) approach that variationally minimizes the random phase approximation (RPA) ground-state energy as a functional of the one-particle density matrix. The GKS-RPA approach enables highly accurate predictions of all observables from derivatives of a single variationally stable energy functional, and leads to remarkable advancements. Intermolecular binding-energies and quasiparticle spectra from GKS-RPA improve significantly upon those from state-of-the-art post-Kohn-Sham RPA or G0W0 theory. Anions, which are often unstable and poorly described by semi-local density functional approximations, are well described within GKS-RPA. Core ionization energies, which are traditionally hard to compute, can be accurately estimated using GKS-RPA; pilot applications for modeling solvation effects in conjunction with X-ray photoelectron spectroscopy will be discussed. Overall, the GKS scheme alleviates some of the most serious problems with semi-local density functional approximations, and paves the way for a new generation of electronic structure methods.

References:

  1. G. Chen, V. K. Voora, M. Agee, S. Balasubramani, and F. Furche. “Random phase approximation methods”, Annu. Rev. Phys. Chem., 2017, 68, 421. 
  2. V. K. Voora, S. G. Balasubramani, and F. Furche. “Variational Generalized Kohn-Sham Approach Combining Random Phase Approximation and Green’s Function Methods”, https://escholarship.org/uc/item/7gf3h1h9.