Pulse with four potentials

Planar Py and Ptz are expected to stack well among nucleobases, and so were used as the probe molecules to measure the hole transfer rate. The oxidation potentials of Py and Ptz were lower than those of the four nucleobases. We examined the sequence and distance dependences of the hole transfer rate by monitoring the decay and formation of the transient absorption of Py,+ and Ptz + during pulse radiolysis of ODN conjugated with Py and Ptz (PtzPy-(n) (n=l 5)). 

For comparison within the chalcogens, the oxidation potentials of the Ph-E-Me series 94, 95b, 96b, and 97b, where E = O, S, Se, Te, respectively, were evaluated by pulse radiolysis.Consistent with the analogous diaryl series, the values for this series indicate that the compounds are increasingly easy to oxidize, with telluride 97b most easily oxidized (0.74 V) and ether 94 least easily oxidized (1.62 V), with these values vs. NHE (Table 10). Eor a broader comparison, series of four or five para-substituted arylmethylsulfides, selenides, and tellurides, 95a-e, 96a-e, and 97a-d were prepared and their values determined in the same manner (Table 10). The same trends were observed, with the thioethers least... 

Rajca and co-workers have studied star-branched and dendritic high-spin polyradicals which are potential organic magnets. Representative data were obtained for the model tetra-anionic compound 55. Three redox waves were observed by cyclic voltammetry and differential pulse voltammetry for a four-electron process between the potentials of -2.00 and -1.20 V (vs. SCE). Electrochemical experiments with these materials have usually been performed at 200 K. The polyradicals, which are less stable for systems with more unpaired electrons, have been characterized by spectroscopic studies, ESR data, and SQUID magnetometiy. 

Figure 11.18 illustrates the principles of application of REMPI to NO (discussed in more detail later). The electronically excited states of NO are shown in Fig. 11.18a and some potential ionization schemes in Fig. 11.18b (Pfab, 1995). Pulsed tunable lasers with wavelengths from 190 to 1000 nm and spectral resolutions of 0.1 cm 1 are readily available. To ionize NO, the absorption of two, three, or four photons is needed. The first photon excites the NO into an intermediate state from which it is ionized using a second or, in some cases, two more photons. The transitions are described as an (n + m) transition, where n is the...

Fig. 3. (a) Ionization potentials for bands E, e2 and e3 in dependence of the excitation energy. Full symbols refer to measurements with 207nm ionization pulse, open symbols to 200nm ionization pulse. The sum of the energy from excitation and ionization pulse is shown as black line. Stars denote the four lowest vertical ionization potentials of 8.4, 8.75, 9.3 and 9.3eV [6], (b) Normalized excitation spectrum showing near degeneracy for the nn states corresponding to bands S and e3. 

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