Optical cycling functionalization of aromatic molecules, towards laser cooling

Multivalent optical cycling centers: towards control of polyatomics with multi-electron degrees of freedom

“…Among conventional AEL-pseudohalogen systems, the MOR motif, which utilizes an oxygen atom to link cycling centers (M) to a functional group (R), has seen enormous success in identifying and engineering laser-coolable systems. 18,19,22,23,25,[27][28][29][49][50][51][52][53][157][158][159][160][161] Other linker paradigms (e.g. S, N, C) have also been explored for monovalent molecules, 18,20,21 particularly systems of reduced symmetry.…”

“…Indeed, it has been widely suggested in the cold molecule community that the existence of a highly polar bond between the OCC and ligand may be an important condition for diagonal FCFs and laser coolability. 9,18,19,[22][23][24][27][28][29] By contrast, multivalent species with p-block OCCs and an oxygen linker (i.e. AlOH) have nonlinear geometries.…”

“…CH 3 OH, C 2 H 6 O). 28,29,152,159,[187][188][189][190][191] Cryogenic yields can be further enhanced via state-selective excitation of reactants, as was demonstrated in the buffer-gas synthesis of YbOH molecules. 192,193…”

“…25 Preliminary results suggest that large, multivalent MSR-type molecules also exhibit structural features conducive to photon cycling, including OCC-localized frontier orbitals with visible-wavelength energy spacings. Combining multi-electron OCC structure with complex electronic ligand degrees of freedom, such as via hypermetallic functionalization, 20,21 or tuning Franck-Condon factors via ligand substitution 22,[27][28][29] offers yet more unexplored design space.…”

“…[10][11][12] In the last five years, laser cooling and optical control have been extended to increasingly complex polyatomic molecules, paving the way towards the high phase space density 13,14 and coherent quantum control [15][16][17] necessary for realizing science applications with cold gases of optically active polyatomic molecules. Simultaneously, theoretical understanding of the features that make molecules amenable to optical cycling and laser cooling has significantly advanced, [18][19][20][21][22][23][24][25][26][27][28][29] leading to the identification of several classes of polyatomics with favorable chemical and structural configurations.…”