ES22-Mihm

Author: Mihm, Tina N - Chemistry, University of Iowa

Title: Using the transition structure factor to reach the thermodynamic limit faster in periodic coupled cluster theory

Abstract: Given the large role metals play in applications like catalysis and surface chemistry, there is a current need for efficient calculations using high-accuracy wavefunction-based methods. For method like coupled cluster, however, these calculations are expensive to run due to the large finite size errors associated with simulating a metal with a periodic finite supercell. Here I will present on our twist angle selection method called “structure factor twist averaging” that we developed to help address this cost. Typically, twist angles are used to change the occupation of orbitals, which breaks degeneracy and produces a different energy at each new twist angle. Averaging over a set of twist angles can reduce finite size error and produces a more balanced description of the system but is expensive to run. Our method uses a property of the solids called the transition structure factor to select the one twist angle that reproduces the average system and contains the smallest amount of finite size errors. Given the direct relationship the transition structure factor has with the energy, we find that it is an effective way to select our special twist angle. I will demonstrate the effectiveness of this method for a range of system sizes and basis sets using a model system. I will also show how our method performs with real systems by applying it to a range of solids.

Other authors:
Schäfer, Tobias (Institute for Theoretical Physics, TU Wien, Vienna, Austria),
Weiler, Laura (Chemistry, University of Iowa, Iowa City, IA),
Ramadugu, Sai Kumar (Chemistry, University of Iowa, Iowa City, IA),
Grüneis, Andreas (Institute for Theoretical Physics, TU Wien, Vienna, Austria),
Shepherd, James J. (Chemistry, University of Iowa, Iowa City, IA)