Next, we review the electronic states of CaOH, which can be described as a hydrogenterminated OCC. Extensive spectroscopic data is available for this molecule . CaOH is one of a few polyatomic molecules that have been laser-cooled, paving the way for advanced quantum-state control experiments . CaOH is a doublet radical with one unpaired electron localized on the metal. The low-lying electronic states of CaOH resemble the states of an alkali atom (Fig. ). Both the ground and the low-lying excited electronic states can be described as a closed-shell core with a single valence electron occupying hydrogen-atomlike orbitals. In the ground state (X state), the unpaired electron is localized on the Ca atom, resembling the 2 S atomic state. The first pair of excited states (A and B states) are 2 P-like states, with degeneracy lifted in non-linear structures. The X→A transition energy for CaOH is around 2 eV. Higher CaOH states also follow this pattern of a localized atomiclike transitions of a single unpaired electron. Below we refer to these states as OCC-like states. This type of states is commonly found in molecules functionalized with the CaOgroup .