Absorption Spectra of Solids from Periodic Equation-of-Motion Coupled-Cluster Theory

We present ab initio absorption spectra of six three-dimensional semiconductors and insulators calculated using Gaussian-based periodic equation-of-motion coupled-cluster theory with single double excitations (EOM-CCSD). The are efficiently by solving a system linear equations at each frequency, giving access to an energy range tens electronvolts without explicit enumeration excited states. assess the impact cost-saving approximations associated Brillouin zone sampling, frozen orbitals, partitioned EOM-CCSD approximation. Although our most converged exhibit line shapes that in good agreement experimental spectra, they uniformly shifted higher energies about 1 eV, which is not explained remaining finite-size errors. tentatively attribute this discrepancy combination vibrational effects electron correlation, i.e., triple above.