UCLA

Electronic excitations, induced by lasers, that decay directly to the initial electronic ground state are called optical cycling transitions. These transitions are used in quantum information and precision measurement for state initialization and readout. One way to prepare initial quantum states is by directly laser-cooling the molecule. In this work, we theoretically predicted molecules, beyond a few atoms in size, which could be laser-cooled, opening the field to increasingly larger polyatomic molecules. The extra degrees of freedom in polyatomic molecules allow novel features for quantum information, simulation, photon entanglement and provide a testbed for studying ultracold chemistry or fundamental physics. We developed design rules, from chemical principles, to tune ultranarrow electronic transitions of large molecules, from small organic to large inorganic complexes. Along the way, various theoretical methods were used or developed, from DFT to ab initio multireference methods to model Hamiltonians, which predicted relevant transitions or lifetimes in these molecules to match experiment.