Time-resolved fluorescence spectrophotometer

Excimer formation in pyrene doped silica glasses prepared by the sol-gel method was studied with a picosecond time-resolved fluorescence spectrophotometer (Yamanaka, 1991). In high dopant concentration ofpyrene, the picosecond time-resolved fluorescence... 

Steady-state and time-resolved fluorescence spectroscopy Absorption and fluorescence spectra were measured with a Hitachi 557 spectrophotometer and a Hitachi 850 spectrofluorometer, respectively. The time-resolved fluorescence spectra were measured with the apparatus reported previously [4,6] in principle, the time-correlated single photon counting system under a low excitation condition. The pulse intensity (540 nm, 6 ps (fwhm)) was in a range of 10 to 10 photons/cm. The time resolution of our optical set-up was 6 ps. Correction of spectral sensitivity and data treatment were carried out as reported previously [4,6]. 

The state of the reaction centres was monitored during all measurements by noting the Qy-band absorption and fluorescence maxima. Steady state absorption measurements were made using a Perkin-Elmer 554 spectrophotometer and fluorescence measurements with a Perkin-Elmer MPF-4 fluorimeter. Samples were maintained at 4 C while all measurements were taken and during time-resolved fluorescence experiments, the samples were also... 

A treatment for analysing the excitation and fluorescence multiwavelength polarized decay surfaces has been given for the case of a mixture of noninteracting species. An improved model for analysis of fluorescence anisotropy measurements has been presented. Limitations to the use of intense excitation pulses in fluorescence and thermal lens spectrophotometers are discussed in terms of optical saturation. Such artefacts can be eliminated by reference to the fluorescence quantum yield of Rhodamine 6G. A model has been given to describe spectral diffusion in time-resolved hole-burning spectroscopy. ... 

Steady state absorption and fluorescence measurements were made using a Perkin-Elmer 554 spectrophotometer and a Perkin-Elmer MPF-4 fluorimeter. Fluorescence lifetimes were measured using time-correlated single photon counting [3]. All of the fluorescence decays from D1/D2 samples were best represented by a sum of four exponentials. Details of the analysis of the decays can be found in [5]. All samples showed a Q band absorption peak of (675.9 0.2) nm before and after all time resolved measurements. 

For example, the Agilent Cary Eclipse spectrophotometer is a versatile instrument that allows fluorescence, phosphorescence, chemiluminescence, bioluminescence, and time-resolved phosphorescence measurements. It uses a xenon flash lamp, red-sensitive PMT, captures a data point every... 

Fig. 4 Time-resolved emission spectnim of hnninescent europium(in) chelate-dyed nanopaiticles (solid line) and terbium(lll) chelate (broken line). Time-resolved Imninescence emission spectra of europium(III) chelate-dyed nanoparticles (107 nm in diameter, obtained from Seradyn, IN) in 1 g/L Triton X-100 solution (excitation at 340 nm) and terbram(III) ions in DELFIA enhancement solution and DELFIA enhancer (PerkinElmer LAS, MA) (excitation at 320 nm) were measured with a Cary Eclipse fluorescence spectrophotometer (Varian Inc., Mulgrave, Australia)...

An additional attractive feature of NSOM is that it can be used to perform localized spectroscopy. For example, the NSOM probe can excite the dye aggregates in Fig. 14 at a particular location and the spectram of the fluorescence emission can be recorded by sending the collected light to a spectrophotometer. The possibility of localized spectral analysis of sample emission dramatically increases the amount of spatially resolved, detailed structural and chemical information that can be determined by NSOM. Time-resolved NSOM spectral studies have also recently... 

Shell Chemical Company), exhibits a maximum at 300 nm, corresponding to that of the model chromophore anisole. The fluorescence intensity decreases monotonically with increasing concentration of 2,4-dihydroxybenzophenone (DHB) and, furthermore, decreases with time on continued excitation (274 nm) in the spectrophotometer. The fluorescence loss with time may be resolved into two exponential decays. Initially, a relatively rapid fluorescence loss is observed within 20 sec, followed by a slower loss. Loss constants for the initial (k ) and secondary (kj) exponential decays for 1.5 ym films (on glass slides) containing varying concentrations of DHB are provided in Table I (entries 1-3). The initial loss constants are seen to decrease more markedly with increasing DHB concentration than the secondary constants. 

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