The performance of approximate EOM‐CCSD for ionization potential and electron affinity of genetic material subunits: A benchmark investigation

We present a benchmark investigation on the performance of various approximate EOM‐CCSD methods for the ionization potential and electron affinity of the genetic material subunits. Our test set consists of 22 molecules, and the canonical EOM‐CCSD method has been used as the reference. Our study shows that the accuracy of approximate methods varies largely for different quantities. However, the pair natural orbital (PNO) based EOM‐CCSD method gives a proper balance between computational cost and accuracy, more suitable than the methods based on perturbative approximation to study properties related to ionization and electron attachment to genetic materials.