Photostability of Coumarin Laser Dyes - a Mechanistic Study Using Global and Local Reactivity Descriptors

Using density functional theory approach, the trend in photostability of fluorescent coumarin laser dyes were investigated with the help global reactivity descriptors. The effect of different basis sets on global reactivity descriptors i.e. electrophilicity index (ω) is studied. The local reactivity descriptors such as Fukui function, local softness and local electrophilicity index have been used to understand the reactive site in the molecule. Photodegradation mechanism of fluorescent coumarin laser dyes in presence of singlet oxygen is explained using density functional theory.