<title>Application of picosecond laser spectroscopy in investigation of initial stages of fluorescence quenching</title>

Examination of the viability of the Smoluchowski–Collins–Kimball model in fluorescence quenching of S2-xanthione

“…The values of the R, D, parameters obtained for some of the systems studied are not in agreement with their values reported earlier on the basis of the time-resolved 17,18 and steady-state 11,17 measurements. This difference can be attributed to the greater instabilities of the earlier used TCSPC system responsible for the changes in the shape and width of the IRF, and the use of a less reliable procedure of measurements, which would not ensure their detection and elimination.…”

“…8 Thioketone molecules are characterized by a short lifetime of the S 2 state in perfluorohydrocarbon solvents ͑from a few dozen to a few hundred picosecond 1,6,9,10 ͒ and are effectively quenched by hydrocarbons ͑typically more than 90% in pure hydrocarbons 1,3 ͒. 10 Since that time the processes of the quenching of aromatic thioketones S 2 -fluorescence have been applied in the investigation of kinetics of fast bimolecular reactions, both in theoretical 14 -16 and experimental works to analyze the steady-state 11,17 and dynamic 17,18 emission measurements. Moreover, the hydrocarbons do not show either electron donor or acceptor properties, so the S 2 -thioketone fluorescence cannot be quenched by the electron transfer.…”

Efficiency of singlet oxygen generation by alloxazines and isoalloxazines

“…The measuring system used to obtain the alloxazine Ñuorescence lifetime is described in detail in ref. 23. The frequency-doubled output of a modelocked, synchronously pumped, cavity-dumped argonÈion/ R6G dye laser system served as the excitation source.…”

Quenching of Excited State Pyrene by Halothane in Poly(oxyethylene)−Poly(oxypropylene)−Poly(oxyethylene) Triblock Copolymers

“…All fluorescence decay curves were observed at the magic angle, 54.7 °, and data were collected with a 512-multichannel analyzer with a minimum of 10 4 counts in the peak channel. This measuring system has been previously described in detail. , The measurements were carried out at 25 °C. The I/III vibronic intensity ratio of pyrene was obtained using a SPEX Fluorolog 1680 instrument.…”