Comparison between the Bethe–Salpeter Equation and Configuration Interaction Approaches for Solving a Quantum Chemistry Problem: Calculating the Excitation Energy for Finite 1D Hubbard Chains
Qi Ou, Joseph Eli Subotnik
We calculate the excitation energies of finite 1D Hubbard chains with a variety of different site energies from two perspectives: (i) the physics-based Bethe-Salpeter equation (BSE) method and (ii) the chemistry-based configuration interaction (CI) approach. Results obtained from all methods are compared against the exact values for three classes of systems: metallic, impurity-doped, and molecular (semiconducting/insulating) systems. While in a previous study we showed that the GW method holds comparative advantages versus traditional quantum chemistry approaches for calculating the ionization potentials and electron affinities across a large range of Hamiltonians, we show now that the BSE method outperforms CI approaches only for metallic and semiconducting systems. For insulating molecular systems, CI approaches generate better results.
Journal of Chemical Theory and Computation•Nov 28, 2017•9 citations