Metal-ligand engineering for molecular optical cycling*

State-controlled polyatomic molecules are promising tools for quantum science, metrology, and studies of fundamental physics and chemistry. The experimental power of polyatomic systems arises primarily from their rich internal structure, which can be leveraged to realize features such as high polarizability and large dipole moments for robust long-range interactions and high-sensitivity metrology, co-magnetometer states and tunable EM sensitivity for error protection, as well as quasi-closed photon cycling channels for enhanced optical control and cooling. Recently, polyatomic molecules of increasing geometric complexity have been found to be compatible with optical cycling and control, and several species have been proposed for use in precision measurement and quantum science. In this abstract, we will discuss efforts towards rational design of new polyatomic optical cycling centers (OCC) using simple bonding and chemical concepts. We will present ab initio results for designing optical cycling properties using novel metal-ligand motifs, such as systems with multi-electron OCCs, as well as higher-than-single OCC-ligand bond order. Our results point to diverse possibilities for designing new, optically controlled polyatomic quantum sensors and bits in previously unexplored chemical space.