The electron pulse irradiation of 10 atm He containing one of CO, CO2, NO, NO2, or N2O at small amounts produced highly excited oxygen atoms O(2p33s,5S), which subsequently disappeared by their reactions with parent molecules. The rate constants have been determined from the absorption decay curves at 777.3 nm O(2p33p,5P)←O(2p33s,5S). The rate constants for the reactions of O(2p33s,5S) with Xe, H2, N2, CH4, and C2H6 could be determined in the irradiation of mixtures of He, O2, and these gases with electron pulses. The upper limit of a quenching rate constant was estimated for Kr. The observed rate constants showed good correlation with the quenching rate constants of Kr(4p55s,3P2) or Xe(5p56s,3P2) by the same gas molecules.
Photoluminescence (PL) properties have been studied for electrodeposited porous ZnO thin films hybridized with luminescent rare earth metal complexes and organic molecules. Nanoporous ZnO films were cathodically electrodeposited from the bath containing eosin Y (EY). Various bridging ligands (BLs) having carboxylic acid group as anchor was loaded to ZnO. These BLs have the moiety to coordinate to metal ions and thus can form complexes on ZnO surface by uptaking metal ions such as Eu 3 +, Tb3+ and Al3+. Fluorescent organic molecules having carboxylic acid group has been chosen and are also attached from their solutions. Some of the hybrid thin films with metal complexes exhibited PL, while none of organic molecules showed PL. Especially efficient were the films with Eu 3 + complexes. Its PL intensity was further increased by capping Eu 3 + with ~-diketones. The quantum efficiency for its PL was determined as 21 %when only the ligand to metal energy transfer is taken into account.
Timeresolved laser induced fluorescence measurement of excited states relaxation constants: Application to the quenching of mercury atoms by NO molecules J. Chem. Phys. 80, 255 (1984); 10.1063/1.446487Quenching rate constants of metastable states of neon, argon, and krypton by mercury atoms Excited halogen atoms in quartet spin states F*(2p 4 3s, 4P 5 r2), CI*(3p 4 4s, 4P 5r 2J, and Br*(4p 4 5s, 4Psd were produced from helium sensitized radiation chemical decomposition of SF 6 , CF 3 Cl, CF 3 Br, and CF2Br2' Quenching rate constants of these excited halogen atoms by simple gas molecules such as O 2 , N 2 , H 2 , CO, CO 2 , NO, N0 2 , N 2 0, CH 4 , C 2 H 6 , and Xe including parent molecules were determined from absorption decay curves at 685.8 nm for F*, 837.5 nm for CI*, and 827.4 nm for Br*. The optical densities were assumed to be proportional to (number of excited atoms per one cubic centimeter)o.9. The quenching rate constants obtained here were compared to those reported of metastable rare-gas atoms and an excited oxygen atom 0* (2p 3 3s, SS2), and further discussed in terms of several theoretical kinetic models.
Porous ZnO films modified with Eu3+ ions were fabricated by electrodeposition and their optical properties were investigated. The porous ZnO films were cathodically electrodeposited in a bath containing eosin Y (EY) dye molecules and the surface of ZnO was modified with Eu3+ ions. Photoluminescence (PL) peaks due to the intra-4f transitions of Eu3+ ions were clearly observed. From the PL excitation (PLE) spectra, it was found that the Eu3+ ions are mainly excited from photoexcited ligands, though another excitation process remains unidentified. Furthermore, the absorption peak energy of the porous ZnO observed in PLE as well as diffuse reflection spectra was 90 meV higher than the A exciton energy of bulk crystals. This energy shift was attributed to the opposing influence of the Burstein–Moss and many-body effects.
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