Laser Cooling Scheme for the Carbon Dimer $¹²$C$₂$

We report on a scheme for laser cooling of ¹²C₂. We have calculated the branching ratios for cycling and repumping transitions and calculated the number of photon scatterings required to achieve deflection and laser cooling of a beam of C₂ molecules under realistic experimental conditions. Our results demonstrate that C₂ cooling using the Swan $d³Π_g leftrightarrow a³Π_u$ and Duck $d³Π_g leftrightarrow c³Σ_u^+$ bands is achievable via techniques similar to state-of-the-art molecular cooling experiments. The Phillips $A¹Π_u leftrightarrow X¹Σ_g^+$ and Ballik-Ramsay $b³Σ_g^- leftrightarrow a³Π_u$ bands offer the potential for narrow-line cooling. This work opens up a path to cooling of molecules with carbon-carbon bonds and may pave the way toward quantum control of organic molecules.