Fluorimeters pulsed-source

For the investigation of triplet state properties a laser flash photolysis apparatus was used. The excitation source was a Lambda Physik 1 M 50A nitrogen laser which furnished pulses of 3.5 ns half-width and 2 mJ energy. The fluorescence decay times were measured with the phase fluorimeter developed by Hauser et al. (11). 

The fluorescence lifetime measurements were performed with a streak camera (Agat SF 3M, VNIIOFI, Russia). A Nd YAG laser with excitation wavelengths of 532 and 266 nm (the second and fourth harmonic of fundamental radiation) was used as a light source. The laser radiation parameters of the fluorimeter were as follows (for 532 nm) pulse energy 160 (ij, duration 20 ps (fwhm), beam diameter 5 mm. The error in determining the fluorescence lifetimes in time intervals of several nanoseconds did not exceed 5 %. In addition to the laser equipment, the Cary 100 spectrophotometer (Varian, Inc., USA) and the Cary Eclipse spectrofluorimeter (Varian, Inc., USA slits width was 5 nm) were used for optical density measurements and fluorescence registration, respectively. 

ISA s (Spex s) Fluorolog Tau-3 lifetime system and Spectronic Instruments SLM-AMINCO 48000 DSCF spectrofluorimeter both use xenon flash lamp excitation (t5 ically 150-450 W) and have modulation frequencies of up to 310 MHz. (Most systems can also be operated as steady-state fluorimeters). SLM also manufactures a multi-harmonic s3rstem based on a pulse- modulated continuous wave light source. 

If the excitation on the spectrofluorimeter is performed by a lamp-monochromator system, CPL excitation spectra can be recorded. CPL spectro-fluorimeters can also be modified to make time-resolved measurements, obviously utilizing a pulsed excitation source. In this case, it should be noticed that the time... 

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