MOLECULAR-ORBITAL STUDY ON PHOTOREACTION OF PEROXY-RADICALS OF POLYTETRAFLUOROETHYLENE

The photoreaction of peroxy radicals of polytetrafluoroethylene (PTFE) was investigated by means of the molecular orbital (intermediate negl ect of differential overlap/spectroscopy-configuration interaction ((I NDO/S-CI)) calculations of the excited states of model compounds for t wo types of radicals, i.e. the endchain peroxy and midchain peroxy rad icals. Calculations showed that the midchain radicals are excited to t he second lowest excited doublet (D-2) state, which is responsible for the photoreaction, with much higher efficiency than the endchain pero xy radicals. The bond order perturbations accompanied by the transitio n from the ground doublet (D-0) state to the D-2 state in the midchain radicals seem to well explain the experimental results.