Single photon counting method

The fluorescence lifetimes were measured by the time-correlated single photon counting method with a mode-locked Ar" ... 

Table 2.5 yields the different values of the mean fluorescence lifetime and of intensity of fluorescein in presence of increased concentrations of KI. Lifetimes were measured with both frequency domain and Time correlated single photon counting methods. Figure 2.20 displays the normalized values at different Kl concentrations. 

S. Kinoshita, T. Kushida, Subnanosecond fluorescence-lifetime measuring system using single photon counting method with mode-locked laser excitation, Rev. Sci. Instrum. 52, 572-575 (1981)... 

C. Lewis, W.R. Ware, The Measurement of Short-Lived Fluorescence Decay Using the Single Photon Counting Method, Rev. Sci. Insfrum. 44, 107-114 (1973)... 

A pulsed N2 laser (2 = 337.1 nm, rp = 8 ns, v = 1 kHz) and a CW HeCd laser (2 = 325 nm) were used for photoluminescence (PL) and lasing measurements. The monochromatized radiation of a Xe lamp (7exc 10"4 W/cm2) was used for PL excitation (PLE) spectra measurements. Low-excitation time-resolved PL measurements were performed at RT using the time-correlated single-photon counting method. X-ray diffraction analysis was performed with a high-resolution diffractometer (PANalytical s X Pert PRO MRD). 

Fig. 8 Experimental setup for a time-correlated single-photon counting method or picosecond single-photon timing method, used for time-resolved luminescence measurements in a range of picoseconds.

New techniques have demonstrated how fast a cyclization can be. Thus, investigation by means of femtosecond-microsecond transient absorption spectroscopy and a time-correlated single-photon counting method of the photoreaction of l,2-bis(2-methyl-3-benzothienyl)perfluorocyclopentene in nonpolar alkane solutions with different viscosities revealed that a ring closure rapidly occurred with a time constant of 450 fs from the antiparallel form, while from the triplet the predominating path was intersystem crossing to the Tj state [5] (Scheme 11.2). 

Time-Conelated Single Photon Counting Methods.89... 

Time-Correlated Single Photon Counting Methods i. Equipment ... 

Fluorescence kinetics of ArOH and ArO in micellar solutions of surfactants with various charges was studied by conventional single photon counting method using numerical deconvolution of decay curves. Concentrations of anionic surfactant - SDS ( 0.1 M ), cationic surfactant - DTAB (0.05 M ) and nonionic surfactant - Triton X-305 and Brij 35 (0.01 M ) were chosen by such a way, that more than 99% of hydro-xycompounds were solubilized in micellar phase and protoly-tic photoreaction take place nearly completely in this phase [11-14]. 

The single photon counting method is used (2, 5), i.e. no more than one fluorescence photon is received by the photomultiplier for one excitation pulse. On receiving this photon, the cathode of the PM ejects a photoelectron ich is amplified in order to produce an electric pulse at the anode. This pulse is sent to the start" inject of a time to amplitude converter (TAG) at a time t, which is compared with the time t ... 

The rate and activation parameters for the intramolecular electron transfers from Os(II)(NH3)5 to Ru(III)(NH3)5 across oligoproline peptide bridges have been determined. The rate constants decrease from 3.1 x 10 s to 50 s as the number of proline units is increase from 1 to 4, and the metal-metal separation distance increases from 12 to 21 A. A time-correlated single photon counting method was employed to investigate the kinetics of the forward [ Ru(II)- Rh(III)] and reverse [Ru(III)<-Rh(II)] intramolecular electron transfer reactions within covalently linked Ru/Rh polypyridine complexes in aqueous, acetonitrile, and methanol solvents. The rate constants for the outer-sphere electron transfer reactions of [Ru(edta)pyz] and... 

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