Comment on "Measurement of a large Chemical Reaction Rate between   Ultracold Closed-Shell ^{40}Ca Atoms and Open-Shell ^{174}Yb^{+} Ions Held in   a Hybrid Atom-Ion Trap"
  We estimate the radiative quenching rate of the $^{40}$Ca - $^{174}$Yb$^{+}$ molecular ion and find that it under-estimates the value reported in recent experiments by about 5 orders of magnitude. We comment on possible explanations for this large discrepancy. 
B. Zygelman, and Robert Hunt
physics.atm-clus physics.atom-ph