Excimers mixed

Figure 6. Comparison of excimer intensity for free and tagged pyrene in novolac films. Film composition ( ) free pyrene in novolac (A) pyrene tagged novolac (o) 19.6 mol% pyrene tagged novolac mixed with untagged novolac. The inset is an expansion of the graph for low pyrene concentrations.

Figure 9.61 ToF mass spectrum of metal-carbon cluster ions (TiC2+ and ZrnCm+ cluster ions) using a titanium-zirconium (50 50) mixed alloy rod produced in a laser vaporization source (Nd YAG, = 532 nmj and ionization by a XeCI excimer laser (308 ). ( . M. Davis, S. J. Peppernick and A. W Castleman, J. Chem. Phys., 124, 164304(2006). Reproduced by permission of American Institute of Physics.)...

In 1977, Scharf and Mattay [123] found that benzene undergoes ortho as well as meta photocycloaddition with 2,2-dimethyl-1,3-dioxole and, subsequently, Leismann et al. [179,180] reported that they had observed exciplex fluorescence from solutions in acetonitrile of benzene with 2,2-dimethyl-l,3-dioxole, 2-methyl-l,3-dioxole, 1,3-dioxole, 1,4-dioxene, and (Z)-2,2,7,7-tetram-ethyl-3,6-dioxa-2,7-disilaoct-4-ene. The wavelength of maximum emission was around 390 nm. In cyclohexane, no exciplex emission could be detected. No obvious correlation could be found among the ionization potentials of the alkenes, the Stern-Volmer constants of quenching of benzene fluorescence, and the fluorescence emission energies of the exciplexes. Therefore, the observed exciplexes were characterized as weak exciplexes with dipole-dipole rather than charge-transfer stabilization. Such exciplexes have been designated as mixed excimers by Weller [181],... 

The PET-induced dehalogenation of aromatics has been extensively investigated. It occurs in the presence of various donors, such as aliphatic and aromatic amines [82-92], alkenes and dienes [91, 93-94], mixed hydrides [95-97], hydroxides [98], carbanions [99-101]. In the absence of an added donor, a viable mechanism involves the excimer (singlet or triplet) and its collapse to oppositely charged radical ions followed by fragmentation of the radical anion [93, 102-104] (a micellar medium has an important effect in this case [103]). 

PLD of crystalline and stoichiometric ferroelectric materials has been successful for a number of materials. For example, crystaUine PbTiOs thin films have been deposited at only 350 °C using a KrF excimer laser (A. = 248 mn). The low deposition temperature makes this a potentially attractive method for directly fabricating ferroelectric/semiconductor hybrid devices. A related solid that is more difficult to prepare in thin film form is PbZri- ThOs. To maintain the Pb stoichiometry and ensure random mixing of Ti and Zr requires careful control of film synthesis conditions. ... 

A peculiarity of the cluster beams discussed above which has to be taken into account in the luminescence studies of intramolecular electron transfer processes is that even under beam conditions optimized for the production of small D-A solute-solvent complexes, the simultaneous appearance of homogeneous clusters is nearly inevitable. Hence excimer fluorescence and the fluorescence of the mixed clusters are often superimposed. Therefore, only the careful characterization of the clusters with respect to their constitution, size and structure can allow the unequivocal assignment of the processes observed. 

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