Filters

1999105

More filters

2019 - 201942020 - 2024101
Reset filters

Settings

End date: 1999 × Start date: 1999 × Has files: Yes ×

Search Results

Now showing 1 - 10 of 105
  • Thumbnail Image
    Item
    Resonance Raman and optical dephasing study of HITCI
    (Routledge : Taylor and Francis Inc., 1999) Kummrow, A.; Ashworth, S.H.; Lenz, K.
    Line shape analysis based on resonance Raman spectra of HITCI is used to determine the details of the vibrational part of the line broadening function. Forced Light Scattering with 20 fs pulses from a Ti: sapphire laser measured optical dephasing probing with an Ar+ laser. The observed response is well described by the line broadening function derived from the fluorescence line shape.
  • Thumbnail Image
    Item
    Molecular dynamics investigated by temporally two-dimensional coherent Raman spectroscopy
    (Routledge : Taylor and Francis Inc., 1999) Lau, A.; Pfeiffer, M.; Kozich, V.; Kummrow, A.
    A six-wave set-up is described to determine molecular dynamics in the condensed phase. Applying two independent time delays between excitation and probe pulses additional information on the dynamics should be obtainable. We show experimentally that such investigations can be carried out with noisy light having intensity fluctuations in the femtosecond region. As first result we found a fast relaxation time in neat nitrobenzene of 100 fs, becoming even faster in mixtures with low viscosity liquids. Switching on a Raman resonance yields a longer relaxation time, which could be explained by an additional contribution by that vibration.
  • Thumbnail Image
    Item
    Coherent motion of low frequency vibrations in ultrafast excited state proton transfer
    (Routledge : Taylor and Francis Inc., 1999) Pfeiffer, M.; Chudoba, C.; Lau, A.; Lenz, K.; Elsaesser, T.
    Photoexcitation of internal proton transfer in the tinuvin molecule causes the excitation of some low frequency vibrational modes which oscillate with high amplitudes in a coherent manner over 700 fs. Such effect is observed for the first time applying two color pump/probe measurement with 25 fs pulses. Based on resonance Raman spectra a normal coordinate analysis of the modes is performed. It is shown that the nuclear movement given by the normal vibration of one of the modes serves to open up a barrierfree proton transfer path.
  • Thumbnail Image
    Item
    The role of spatial variability of soil moisture for modelling surface runoff generation at the small catchment scale
    (Göttingen : Copernicus GmbH, 1999) Bronstert, A.; Bárdossy, A.
    The effects of spatial variability of soil moisture on surface runoff generation at the hillslope and small catchment scale were studied. The model used is physically based accounting for the relevant hydrological processes during storm runoff periods. A case study investigating the effects on runoff generation in a loessy small catchment is presented. In this study the storm rainfall response was modelled using different distribution patterns of the initial soil moisture content, and where different initial soil moisture fields were generated by using both interpolation methods and stochastic simulation methods. It is shown that spatial variability of pre-event soil moisture results in an increase in runoff production compared to averaged values. It is of particular importance to note the combined organised/stochastic variability features, that is, the superposition of systematic and random features of soil moisture dominate local generation of surface runoff. In general one can say that the stronger the organised heterogeneity is, the more important is an adequate and refined interpolation technique which is capable of accounting for complex spatial trends. The effects of soil moisture variations are of particular importance for storms, where the produced runoff volume is just a small fraction of precipitation.
  • Thumbnail Image
    Item
    Wirkung von Klimaänderungen auf Vegetation: Entwicklung eines allgemeinen Modells für die Klimafolgenforschung : Abschlußbericht
    (Potsdam : Potsdam-Institut für Klimaforschung, 1999) Cramer, Wolfgang
    [no abstract available]
  • Thumbnail Image
    Item
    Crystal structure of distrontium praseodym gallium pentaoxide, Sr2PrGaO5
    (München : R. Oldenbourg Verlag GmbH, 1999) Gesing, T.M.; Uecker, R.; Buhl, J.-C.
    GaO5PrSr2, tetragonal, I4/mcm (No. 140), a = 6.8441(2) Å, c = 11.2534(4) Å, V = 527.1 Å3, Z = 4, R(P) = 0.035, wR(P) = 0.052, R(I) = 0.038, T = 295 K. © by Oldenbourg Wissenschaftsverlag.
  • Thumbnail Image
    Item
    Crystal structure of praseodym gallate, Pr4Ga2O9
    (München : R. Oldenbourg Verlag GmbH, 1999) Gesing, T.M.; Uecker, R.; Buhl, J.-C.
    Ga2O9Pr4, monoclinic, P121/c1 (No. 14), a = 7.8256(4) Å, b = 11.0322(5) Å, c = 11.4959(7) Å, β = 109.187(3)°, V = 937.4 Å3, Z = 4, R(P) = 0.026, wR(P) = 0.034, R(I)= 0.033, T = 295 K.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Crystal structure of strontium praseodym trigallium heptaoxide, (Sr0.5Pr0.5)2Ga3O7
    (München : R. Oldenbourg Verlag GmbH, 1999) Gesing, T.M.; Uecker, R.; Buhl, J.-C.
    Ga3O7PrSr, tetragonal, P4̄21m (No. 113), a = 8.0198(2) Å, c = 5.2991 (1) Å, V = 340.8 Å3, Z = 2, R(P) = 0.026, wR(P) = 0.040, R(I) = 0.025, T = 295 K.
  • Thumbnail Image
    Item
    Regelungstheorie
    (Oberwolfach-Walke : Mathematisches Forschungsinstitut Oberwolfach, 1999) Thoma, Manfred
    [no abstract available]