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Publication Type: search.filters.UBSTyp.KonferenzbeitragSubject: search.filters.subject.530Institute: search.filters.UBSInstitut.Sonstige EinrichtungStart date: 1981End date: 1986

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Now showing 1 - 8 of 8
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    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.
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    Influence of defects on the splitting of the acceptor ground state in silicon
    (1984) Ambrosy, Anton; Lassmann, Kurt; Goer, Anne M. de; Salce, Bernard; Zeile, Heinrich
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    Spectroscopic properties of kekulene
    (1981) Schweitzer, Dieter; Hausser, Karl H.; Diederich, Francois; Staab, Heinz A.; Vogler, Helmut
    Kekulene [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.
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    Prospects of testing aspheric surfaces with computer-generated holograms
    (1981) Tiziani, Hans J.
    For testing aspheric surfaces, computer generated holograms are frequently used. Some methods of generating the holograms as well as a comparison of in-line and off-axis computer generated holograms will be discussed. Furthermore, examples tested will be analysed from the stand point of an industrial testing procedure.
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    Phonon absorption-spectroscopy in the presence of strong elastic phonon scattering
    (1986) Mebert, Joachim; Koblinger, Otto; Döttinger, Siegfried; Eisenmenger, Wolfgang
    In this work we show that in the presence of a strong phonon scattering background absorption structures can only be well resolved by reducing sample thickness to the phonon mean free path. This mean free path can be determined by analyzing the pulse shape of 285 GHz phonons. By reducing sample thickness to the appropriate value of 0,3mm the 21,2 cm -1 crystalline field transition in CaF 2:Er 3+ could be evaluated with the very high resolution of 5 GHz. In experiments performed on a 1mm thick LaF 3 Er 3+ sample we observed an absoption line at 14,2 cm -1 not visible in FIR absorption measurements.
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    Towards a self-consistent modelling of pulsar magnetospheres
    (1986) Herold, Heinz; Ertl, Thomas; Ruder, Hanns
    The numerical modelling of the general case of an obligue rotator is a very complicated time-dependent three-dimensional problem and in its full extent probably outside the capacity of present-day computers. A considerable simplification occurs if one can assume that the essential effects may be understood by modelling the magnetosphere of an aligned rotator (where the rotation axis is parallel to the magnetic axis of the neutron star). This assumption is only reasonable for small obliguenses, since by this approach all electromagnetic wave effects are not taken into account. An advantage, however, is that unipolar induction, which should be responsible for populsting the magnetosphere with charged particles pulled out from the neutron star surface via field emission, can be studied purity.
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    Shallow traps correlated with deep impurities in silicon as obtained by phonon induced conductance
    (1986) Burger, Wilfried; Lassmann, Kurt; Holm, Claus; Wagner, Peter
    At low temperatures shallow neutral donors and acceptors in silicon can bind an extra carrier to form the so-called D- and A+ centers. With the method of phonon-induced electrical conductivity (PIC) we find the same threshold energies for the detachment of these carriers associated with the shallow impurities P and B, as have been obtained previously by FIR measurements. This shows that the detachment is by a one-phonon process. We find that there is no central cell correction for the binding to the deeper acceptors Al and Ga, whereas for In+ the binding energy is as large as 5,8 meV. We interprete this dependence on acceptor species as another example of the shallow-deep instability of the binding energy with the variation of the central cell potential.
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    Analysis of hydrogen Rydberg spectra in a uniform magnetic field: uncovering the transition from regularity to irregularity in a real quantum system
    (1986) Wunner, Günter; Woelk, Ulrich; Zech, Ingrid; Zeller, Gudrun; Ertl, Thomas; Geyer, Florian; Steitz, Arno; Schweizer, Wolfgang; Ruder, Hanns
    Studies of the behaviour of quantum systems in a range of energy where their classical counterparts undergo transitions from regularity to irregularity, as manifested in phase space by the gradual destruction of invariant tori, to date have largely been confined to model Hamiltonian systems such as harmonic oscillators with cubic, quartic, or higher-degree polynomial corrections, or the stadium problem. We show that phenomena which have turned out characteristic of the onset of "quantum stochasticity" in these model systems can in fact be recovered in the quantal energy spectra of a "real" physical system, viz. spectra of hydrogen Rydberg atoms in strong magnetic fields. This implies that one has a simple prototype system at hand in which to study - not only in theory but also in experiment, quantitatively and in detail, and as a function of a continuously tunable external parameter - phenomena that are expected to be typical of the quantum properties of nonintegrable systems in general.