Excited state and free radical properties of rhodamine dyes in aqueous solution: A laser flash photolysis and pulse radiolysis study

Abstract

The techniques of pulse radiolysis and laser flash photolysis have been used to obtain both novel and improved data on the yields, lifetimes and absorption spectra of the triplet state, radical anion and radical cation of a number of rhodamine dyes. These parameters have also been measured for the widely-studied rhodamine 6G and are compared with previous data obtained using different techniques. In view of the importance of rhodamine dyes in laser action, in photobiology and in other biological processes, the results of this study provide key data on the photophysical and free radical properties of this important class of dyes.