The Theoretical Estimation of the Bioluminescent Efficiency of the Firefly via a Nonadiabatic Molecular Dynamics Simulation

The firefly is famous for its high bioluminescent efficiency, which has attracted both scientific and public attention. The chemical origin of firefly bioluminescence is the thermolysis of the firefly dioxetanone anion (<b>FDO</b>^<b>–</b>). Although considerable theoretical research has been conducted, and several mechanisms were proposed to elucidate the high efficiency of the chemi- and bioluminescence of <b>FDO</b>^<b>–</b>, there is a lack of direct experimental and theoretical evidence. For the first time, we performed a nonadiabatic molecular dynamics simulation on the chemiluminescent decomposition of <b>FDO</b>^<b>–</b> under the framework of the trajectory surface hopping (TSH) method and theoretically estimated the chemiluminescent quantum yield. The TSH simulation reproduced the gradually reversible charge-transfer initiated luminescence mechanism proposed in our previous study. More importantly, the current study, for the first time, predicted the bioluminescence efficiency of the firefly from a theoretical viewpoint, and the theoretical prediction efficiency is in good agreement with experimental measurements