Frequency Dependent Polarizability for 1D Periodic Systems at Coupled Cluster with Single and Double Excitations Level

TL;DR

This paper presents the first implementation of frequency-dependent polarizability calculations for 1D periodic systems using CCSD with periodic boundary conditions, advancing quantum simulations of solid-state optical properties.

Contribution

It introduces a novel implementation of frequency-dependent polarizability for 1D periodic systems at the CCSD level with PBCs, in an open-source software framework.

Findings

Polarizability tensor elements invert when passing from molecule to periodic chain

Convergence towards the thermodynamic limit depends on k-space sampling

Remaining issues in defining the dipole operator for periodic systems

Abstract

We report the first implementation of the frequency-dependent electric dipole-electric dipole polarizability for 1D periodic systems computed with the coupled cluster with single and double excitations (CCSD) method with periodic boundary conditions (PBCs). The implementation is performed in the CCResPy open-source software, based on Python and the NumPy library. The complete equations and many details of the implementation are discussed. The test calculations show the impact on this linear response property of passing from a single molecule to a periodic chain, where the relative magnitude of the polarizability tensor elements is inverted. This work also explores the convergence towards the PBC thermodynamic limit with k-space sampling, and some remaining issues in the definition of the electric dipole operator for periodic systems. This work represents a significant step forward for the simulation of optical response properties for solid-state materials with accurate and systematically improvable quantum mechanical methods.