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Excimer
About: Excimer is a research topic. Over the lifetime, 3725 publications have been published within this topic receiving 75104 citations.
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TL;DR: In this paper, a number of calix-arene-based fluorescent chemosensors containing amide as a binding site and quinoline as a fluorogenic unit have been synthesised and characterized by a single crystal X-ray diffraction study.
Abstract: A number of calix[4]arene-based fluorescent chemosensors containing amide as a binding site and quinoline as a fluorogenic unit have been synthesised and characterized by a single crystal X-ray diffraction study. These compounds have been designed with variations in conformation and steric crowding in the calix moiety to investigate its effect on ion selectivity and thereby on excimer emission. The ion-binding property of these fluoroionophores has been investigated with a large number of cations and anions and the ion-recognition event was monitored by luminescence, UV-Vis and 1H NMR (for anions) spectral changes. Out of a large number of cations, Hg2+, Pb2+, Fe3+ and Cu2+ exhibited strong complexation with all of the ionophores, as evident from luminescence and UV-vis spectroscopy. In the case of anions, F− and HSO4− exhibited strong complexation with two of the ionophores, as shown by fluorescence and NMR spectroscopy. Interestingly, complexation with metal ions resulted in a new band at lower energy due to excimer emission, which was not observed for anions. The binding constants for all of the three fluoroionophores with strongly interacting ions have been determined from fluorescence, UV-vis and NMR titration data. The DFT calculations for all of the three compounds were performed and the results show that the modulation of frontier molecular orbital energies upon complexation of metal ions causes the fluorescent excimer emission.
35 citations
TL;DR: Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose.
Abstract: An experimental investigation of optical fiber transmission of high power excimer laser radiation is presented. Different types of commercially available UV fiber have been tested, measuring energy handling capabilities and transmission losses of short samples at the XeCl (308-nm) and KrF (249-nm) wavelengths by using a standard excimer laser. A power density dependent damage process has been observed over 1 GW/cm(2). Fiber losses due to different radii of curvature are also reported. Experimental results have been examined to evaluate the effectiveness of excimer laser transmission through optical fibers for such medical uses as laser angioplasty, including also a comparison between the use of KrF or XeCl emission lines for this purpose. Finally, optimum excimer laser characteristics to increase the energy coupling in fibers are discussed.
34 citations
TL;DR: The naphtalene excimers, produced upon selective excitation of the van der Waals trimer and tetramer, were studied by photodissociation spectroscopy with fluorescence detection as discussed by the authors.
Abstract: The naphtalene excimers, produced upon selective excitation of the van der Waals trimer and tetramer, are studied by photodissociation spectroscopy with fluorescence detection These excimers absorb efficiently in the near-IR and visible regions, with a maximum at 700 nm, which results in a strong depletion of the excimer fluorescence The absorption band is assigned to a transition between the excimer states, both originating from configuration interaction of the 1 L a molecular excitation states and the charge resonance states
34 citations
TL;DR: In this paper, the excited equilibrium state of charge transfer molecular complexes in polar solvents is described by the use of the nonlinear Schrodinger equation presented in our previous paper.
Abstract: The excited equilibrium state of molecular complex in solution is described by the use of the nonlinear Schrodinger equation presented in our previous paper. The excited equilibrium state of charge-transfer molecular complex or the equilibrium state of exciplex in polar solvents is quite polar and quite different from the excited Franck-Condon state, and has large tendency to dissociate to solvated ions. These theoretical results are confirmed by the laser photolysis experiments on the excited states of the molecular complexes.
34 citations
TL;DR: In this article, the pyrene label was incorporated into the polystyrene backbone by either reacting 1-pyrenemethoxide with a chloromethylated poly styrene backbone to yield the GrE−PS series, or copolymerizing styrene with 4-1-methoxymethylmethylmethylstyrene (4-methylamide) to yield CoA−PSseries, or polymerizing α,ω-dicarboxyl end-capped polystyrenes with l-lysine-1 pyrenemethylam
Abstract: Four types of pyrene-labeled polystyrene samples (Py−PS) were prepared and the process of excimer formation between the pyrene labels was characterized by steady-state and time-resolved fluorescence to assess the effect the mode of pyrene incorporation into a polymer has on the kinetics of excimer formation. The pyrene label was incorporated into the PS backbone by either (1) reacting 1-pyrenemethoxide with a chloromethylated polystyrene backbone to yield the GrE−PS series, (2) copolymerizing styrene with 4-(1-pyrenyl)methoxymethylstyrene to yield the CoE−PS series, (3) copolymerizing styrene with N-(1-pyrenylmethyl)acrylamide to yield the CoA−PS series, or (4) polymerizing α,ω-dicarboxyl end-capped polystyrenes with l-lysine-1-pyrenemethylamide dihydrochloride to yield the ES−PS series. Steady-state and time-resolved fluorescence experiments demonstrated that the long and flexible linker of GrE−PS and CoE−PS enabled more efficient excimer formation than the short and rigid linker of CoA−PS, and that spac...
34 citations