Accuracy of projected atomic virtual orbital space in embedding applications

Abstract

The performance of the recently suggested projected atomic orbitals (PAO) approach as the virtual space in excited state projection-based embedding applications is analyzed. The role of the parameters in the PAO generation is discussed and the impact of different choices is evaluated on the ground state of the stacked formaldehyde and pyrrole dimers. A comparison of excitation energies obtained with PAOs and localized virtual orbitals is given and the role of diffuse basis functions is discussed using a benchmark set from previous studies.