Abstract
Firefly luciferin (Ln) is an absorbing substance which showing a high quantum efficiency of the bioluminescence. Several proposals about the mechanism of the luminescence in this system have been explained by investigators. A dioxetane structure exists within the intermediate of Ln and plays an important role to occure the emission. In this report, we attempt to calculate the electronic structures of the dioxetane and to correlate the calculated results with the experimental observations as a first step to recognize the mechanism of the bioluminescence of Ln. Obtained results show that the 2p electrons of O and C are important as to the electronic excitations of the luminescence. The calculated excitation energy agrees with the observed value in spite of a simplified system.
