Universität Stuttgart
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Item Open Access Electronic spectra and triplet state properties of superphane(1986) Schweitzer, Dieter; Hausser, Karl H.; Vogler, Helmut; Staab, Heinz A.; Boekelheide, VirgilThe emission and the zero-field splitting parameters D and E of the superphane 1 and the [25](1,2,3,4,5)-cyclophane 2 are investigated. The large number of six and five methylene bridges, respectively, leads to a more rigid molecular frame and to a smaller transanular distance as compared to other [2.2]cyclophanes. The experimental results exhibit characteristics features which are due to these unusual properties; they are discussed and compared with semi-empirical Π-electron calculations.Item Open Access Optical detection of magnetic resonance (ODMR) of triple-layered phanes(1981) Melzer, Guenter; Schweitzer, Dieter; Hausser, Karl H.; Staab, Heinz A.; Zapf, Udo-Item Open Access ODMR of triplet states of organic electron donors(1986) Grimm, Hans; Schweitzer, Dieter; Hausser, Karl H.; Keller, Heimo J.Energies of the first excited triplet states and triplet zero field splitting parameters /D/ and /E/ of several organic donors - usually used for the preparation of organic metals and superconductors - are reported.Item Open Access Spectroscopic properties of kekulene(1981) Schweitzer, Dieter; Hausser, Karl H.; Diederich, Francois; Staab, Heinz A.; Vogler, HelmutKekulene [1,2] is the first example of a new class of aromatic compounds in which the annelation of six membered rings leads to a cyclic system enclosing a cavity with hydrogen atoms.Item Open Access Optical detection of magnetic resonance (ODMR) of naphthalenophanes(1981) Schweitzer, Dieter; Hausser, Karl H.; Blank, Norman E.; Haenel, Matthias-Item Open Access Electron spin echo determination of spin diffusion in the one-dimensional conductor (fluoranthenyl)2+(PF6)x-(SbF6)1-x-(x ≈ 0.5)(1983) Sigg, Jakob; Prisner, Thomas; Dinse, Klaus Peter; Brunner, Hermann; Schweitzer, Dieter; Hausser, Karl H.-Item Open Access Overhauser effect experiments on the one-dimensional conductor (perylene)2+PF6-·2/3THF(1984) Brunner, Hermann; Hausser, Karl H.; Keller, Heimo J.; Schweitzer, DieterWe have measured the Overhauser enhancement of the protons and the 19F-nuclei of the one-dimensional conductor (perylene)2+PF6-·2/3THF in its metallic phase at room temperature. The enhancement factor V was found to be VP=+320±20 for the protons and VF=+175±40 for the 19F-nuclei indicating a predominantly scalar interaction with the conduction electrons in both cases.Item Open Access Electronic properties of kekulene(1982) Schweitzer, Dieter; Hausser, Karl H.; Vogler, Helmut; Diederich, Francois; Staab, Heinz A.The fluorescence and phosphorescence of kekulene in a host matrix of polycrystalline tetrachlorobenzene are investigated, together with the triplet zero field splitting parameters |D| and |E| obtained by ODMR in zero field. The D value is also calculated within a semi-empirical π-theory and compared with experiment. It could be shown that the triplet state energies of a number of different sites of kekulene in the host matrix and the zero field splitting parameters are related, in first order, by spin orbit interaction.Item Open Access Electron-spin-echo experiments on the one-dimensional conductor [(fluoranthene)2]+[(PF6)x(SbF6)1-x]- (x≈0.5)(1983) Sigg, Jakob; Prisner, Thomas; Dinse, Klaus Peter; Brunner, Hermann; Schweitzer, Dieter; Hausser, Karl H.The electron-spin-echo decay function was determined for the conducting phase of [(C16H10)2]+X- in the temperature range 183-300 K. The decay function exhibited an exp[-(γt)3/2] dependence, characteristic of one-dimensional spin diffusion. The ratio 5×106≤D∥/D⊥≤5×108 for the inner-stack-to-out-of-stack diffusion rates was determined from the characteristic time t0, at which the electron-spin-echo decay function changed to the "conventional" exp(-2γ′τ)) form. The deduced value 2×1013≤D∥≤2×1016 rad/s is consistent with the bulk dc conductivity and with recently determined nuclear spin-lattice relaxation rates. The overall assumption of highly mobile electronic spins was confirmed by an Overhauser-type experiment.Item Open Access ZFS-tensor of the triplet states of [2.2]phanes as studied by ESR(1981) Bär, Monika; Dinse, Klaus Peter; Goldacker, Wilfried; Hausser, Karl H.; Schweitzer, Dieter; Zimmermann, Herbert; Krieger, Claus-