Time-resolved spectra of the

Fig. 3 Time resolved spectra of the triplet of ZnTPP in reversed micelles of BHDC (w=0) in the absence of AQS. ...

Figure 2 UV-vis spectra obtained from the time-resolved spectra of the reaction in nonacidified MeOH at —50°C of [Fe(dapsox)(OMe)(MeOH)] (a), intermediate [Fe(dapsox)(NCS)(MeOH)] (b) and [Fe(dapsox)(NCS)2] (c). Experimental conditions [Fe(III)] = 5 X 10 M, [SCN ] = 0.3 M. Inset corresponding kinetic trace fitted to a double-exponential fimction...

Figure 7.17 shows time-resolved spectra of the reaction of CuCyDTA " (copper cyclohexanediaminetetraacetate) with ethylenediamine (en). This reaction involves a mixed complex [39] as represented in the following equations ... 

Figure 7.17. Time-resolved spectra of the reaction of CuCyDTA with ethylenediamine. The scan time for one spectrum was 20 msec spectra were taken every 2 sec. (jCyDTA — cyclohexanediaminetetraacetate). Reprinted with permission from R. E. Santini, M. J. Milano, and H. L. Pardue, Anal. Chem., 45, 915A (1973), by permission of the authors and publisher. Copyright 1973 by the American Chemical Society.

Fig. 14.16 Time-resolved spectra of the sample ScVO4 1.0%Bi -" on excitation into 265 nm. The collected time ranges from 0 to 50 ps. Reproduced from Ref. [35] by permission of American Chemical Society...

FIGURE 22. Time-resolved spectra of the photon emission during different time periods following an initial photon burst. 

The events taking place in the RCs within the timescale of ps and sub-ps ranges usually involve vibrational relaxation, internal conversion, and photo-induced electron and energy transfers. It is important to note that in order to observe such ultrafast processes, ultrashort pulse laser spectroscopic techniques are often employed. In such cases, from the uncertainty principle AEAt Ti/2, one can see that a number of states can be coherently (or simultaneously) excited. In this case, the observed time-resolved spectra contain the information of the dynamics of both populations and coherences (or phases) of the system. Due to the dynamical contribution of coherences, the quantum beat is often observed in the fs time-resolved experiments. 

Most of the kinetic models predict that the sulfite ion radical is easily oxidized by 02 and/or the oxidized form of the catalyst, but this species was rarely considered as a potential oxidant. In a recent pulse radiolysis study, the oxidation of Ni(II and I) and Cu(II and I) macrocyclic complexes by SO was studied under anaerobic conditions (117). In the reactions with Ni(I) and Cu(I) complexes intermediates could not be detected, and the electron transfer was interpreted in terms of a simple outer-sphere mechanism. In contrast, time resolved spectra confirmed the formation of intermediates with a ligand-radical nature in the reactions of the M(II) ions. The formation of a product with a sulfonated macrocycle and another with an additional double bond in the macrocycle were isolated in the reaction with [NiCR]2+. These results may require the refinement of the kinetic model proposed by Lepentsiotis for the [NiCR]2+ SO/ 02 system (116). 

Fig. 13. Time-resolved spectra for the reaction of K[Fe (Porph)(02 )] and TBPH (2,4,6-tri( -butyl)phenol) at 25°C in DMSO.

Our results are rather similar to those of Wojtowicz (1991). Two narrow lines at 689 and 706 nm with long and slightly different decay times together with broad bands at 750 and 790 nm with short decay times characterized time resolved spectra of kyanite at 300 K (Fig. 4.46). Those data clearly indicate that we have emissions coming from the Cr in three different sites site A with a strong crystal field - doublet i -lines at 689 and 706 nm, site B with a weak crystal field - quartet broad band at 750 nm accompanied by only one doublet i -line at 704 nm which may be detected only at low temperatures, and site C with a weak crystal field - quartet broad band at 790 nm. 

The study by Bhaumik et al. (63) of the time-resolved spectra of europium emissions from the same compound is quite interesting. Their data were taken on microcrystals at 77°K, again using a stroboscopic technique. Figure 41 shows the result in which excitation was again applied to the organic part of the molecule. 

The rotationally resolved spectra of the doubly hydrogen-bonded complexes (HCOOH)2 and (CH3COOH)2 have been measured for the first time by a spectroscopic technique. Rotational constants and the PT evaluated from the fitting of the fs DFWM spectra are in good agreement with results from ab initio calculations. The values of the CD constants have been obtained from the analysis based on a new general nonrigid asymmetric rotor approach. 

Figure 12. A series of time-resolved spectra of HC1 emission taken after initiation of a chain reaction by laser photolysis of Cl2 in the presence of C2H6. At the earliest time delay shown here HC1 is highly excited, and relaxes by collisional deexcitation at later times. Reproduced with permission from Ref. 86.

Figure 7.35 (a) Time-resolved spectra of a molecular emission in the course of solvent relaxation. 

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