Abstract

The photochemical reaction in the hole-burning process of metal-free porphyrins has been ascribed to the photoinduced tautomerism of central two protons through the triplet state¹⁾. For further understanding of the reaction mechanism, one of the useful approachs is to modify the lifetimes of the excited states without changing energy levels. The population of electronic states under laser-excitation will be influenced considerably, but the electronic structure itself will not change so much. The quantum yield of the hole-formation will be also influenced if it depends mainly on the population of the state where the reaction starts. In this study, we modified the lifetimes by enhancing the intersystem crossing rates with a paramagnetic effect of copper(II) atom. The starting point of the reaction will be discussed with the quantum yields and the population of the states.

© 1991 Optical Society of America