Equation-of-motion coupled-cluster methods for open-shell
and electronically excited species: The hitchhiker's guide to Fock
A. I. Krylov
Ann. Rev. Phys. Chem. 59, 433 – 462
Equation-of-motion coupled-cluster approach is a versatile electronic
structure tool that allows one to describe a variety of multi-configurational
wavefunctions within single-reference formalism.
This review provides a guide to the established EOM methods
illustrated by examples demonstrating which types of target states are
currently accessible by EOM. The focus is on applications of EOM-CC
to electronically excited and open-shell species.
The examples emphasize the advantages of
EOM for selected situations, i.e., interacting states of different nature,
JT and pseudo-JT states, dense manifolds of ionized states, diradicals,
triradicals, etc. The limitations and caveats
are also discussed, and practical solutions to some problematic
situations are offered. The review also touches upon some
formal aspects of the theory and important current developments.