The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
J. Fink - One of the best experts on this subject based on the ideXlab platform.
-
Pulsed EPR on the photoexcited triplet state of C60 fullerene
Chemical Physics Letters, 1992Co-Authors: M. Bennati, A. Grupp, Michael Mehring, Klaus-peter Dinse, J. FinkAbstract:Abstract We report on the observation of two different triplet states in photoexcited C 60 fullerene molecules. The following fine structure parameters were determined from spectral fits to the triplet Powder Spectrum: | D 1 | = 0.0117 cm −1 (12.5 mT), | E 1 | = 0.0014 cm −1 (1.5 mT) and | D 2 | = 0.0047 cm −1 (5 mT), | E 2 | = 0.0 cm −1 . Below 10 K mainly triplet 1 was observed, whereas triplet 2 appeared only with increasing temperature. It is thermally activated with an activation energy Δ E ≈ 17 meV. Due to motional narrowing the parameters D 1 and E 1 decrease slightly at higher temperatures. Depopulation kinetics as well as spin-lattice relaxation rates were determined.
Carlos J. Serna - One of the best experts on this subject based on the ideXlab platform.
-
Infrared optical properties of zircon
Materials Research Bulletin, 1994Co-Authors: Carlos Pecharromán, Manuel Ocaña, Pedro Tartaj, Carlos J. SernaAbstract:We have measured the infrared reflectance Spectrum of the ordinary ray of a zircon single crystal in order to determine the optical constants of the Eu modes. With the obtained data and the optical parameters corresponding to the A2u modes (extraordinary ray) taken from literature, we have analyzed the absorption spectra of zircon Powders by using the Maxwell-Garnett Theory (MGT) and the Effective Medium Theory (EMT), which take into account the effects of the shape and aggregation state of the particles. This analysis showed that although MGT can account for the main vibrational zircon features, EMT seems a more appropriate approach to interpret the Powder spectra since it gives a more accurate estimation of the particle aggregation effects. From the above study, the assignment of the bands in the infrared Powder Spectrum of zircon has also been carried out.
Shihua Wang - One of the best experts on this subject based on the ideXlab platform.
-
The first solid-state 171Yb nuclear magnetic resonance spectra.
Solid state nuclear magnetic resonance, 1994Co-Authors: Xi-an Mao, Xinhua Zhao, Shihua WangAbstract:The first Powder and magic-angle spinning (MAS) experiments on 171Yb are reported. The divalent ytterbium compound RbYbI3 was studied by solid-state 171Yb nuclear magnetic resonance (NMR) and a Powder Spectrum of axial symmetry was obtained. The principal components of the chemical shielding tensor were determined as sigma 11 = sigma 22 = -62 ppm and sigma 33 = 124 ppm. An inversion-recovery experiment showed an anisotropic relaxation behavior with the parallel component relaxing faster than the perpendicular component (T1 perpendicular = 426 ms, T1 parallel = 298 ma). The natural line width of 800 Hz, which corresponds to an effective T2 of 0.4 ms, was obtained from the MAS Spectrum.
J.-p. Legros - One of the best experts on this subject based on the ideXlab platform.
-
Stereochemistry of [Cu(Tridentate Ligand)2] entities. crystal and molecular structure and electronic properties of [Cu(tedpa)2](PF6)2 (tedpa = N,N,N′N′-tetraethyl pyridinedicarboxamide)
Polyhedron, 1996Co-Authors: Julia García-lozano, Lucia Soto, José-vicente Folgado, Emilio Escrivà, J.-p. LegrosAbstract:Abstract The crystal and molecular structure of [Cu(tedpa) 2 ](PF 6 ) 2 have been determined by X-ray diffraction methods. The compound is built up of cationic [Cu(tedpa) 2 ] 2+ and PF 6 groups. The coordination geometry about the copper atom can be described as an elongated and strongly distorted octahedron (CuN 2 O 3 O′ chromophore). The EPR Powder Spectrum is slightly orthorhombic and from the g values and the partially resolved hyperfine components some covalency and molecular parameters have been estimated. EPR single crystal experiments indicate that the g -tensor axes follow the molecular bonds. Copyright © 1996 Elsevier Science Ltd
M. Bennati - One of the best experts on this subject based on the ideXlab platform.
-
Pulsed EPR on the photoexcited triplet state of C60 fullerene
Chemical Physics Letters, 1992Co-Authors: M. Bennati, A. Grupp, Michael Mehring, Klaus-peter Dinse, J. FinkAbstract:Abstract We report on the observation of two different triplet states in photoexcited C 60 fullerene molecules. The following fine structure parameters were determined from spectral fits to the triplet Powder Spectrum: | D 1 | = 0.0117 cm −1 (12.5 mT), | E 1 | = 0.0014 cm −1 (1.5 mT) and | D 2 | = 0.0047 cm −1 (5 mT), | E 2 | = 0.0 cm −1 . Below 10 K mainly triplet 1 was observed, whereas triplet 2 appeared only with increasing temperature. It is thermally activated with an activation energy Δ E ≈ 17 meV. Due to motional narrowing the parameters D 1 and E 1 decrease slightly at higher temperatures. Depopulation kinetics as well as spin-lattice relaxation rates were determined.