Dissociation characteristics of light absorbed dioxin analogues calculated by density functional theory

Yamauchi, Toshihiko; Kobayashi, Seiji*; Ito, Shinichi*; Yamazaki, Kazuhiko; Kamei, Yasutaka*; Kanno, Yoshinori*

Using DFT two benzene rings in Co-PCB are found to be twisted on the bond axis, whose angle is 37.8 in Co-PCB(3,3,4,4,5), and it is 90 in PCB(1,1,2,2,3,3,4,4,5,5), and two benzene rings of TCDD or TCDF are in the same plane. Next, the dissociation of chlorine atom from dioxin is realized using the violet light below 318 nm as the bond dissociation energy 3.83.9 eV estimated by the energy difference between the dioxin and the chlorine atom plus dioxin radical. The orbital bond energy is estimated to be 4.15.5 eV, and the zero-point energy is also estimated to be 0.381.65 eV. The bond dissociation energy is inverse proportion to the number of chlorine atoms in dioxins. On the other hand, the dissociation reaction by the extract of chlorine using hydrogen atom is successfully analysed. The reaction times of dechlorination, or the extract reaction of chlorine and the photolytic process, are 2240 fs.