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Basing on a recent paper and a linear response theory for highly excited systems far from equilibrium the macroscopic dielectric function (MDF) is evaluated for highly excited noble metal layers by means of the density-density Green's function in RPA with a crude consideration of the band structure of the metal. The evaluation of the time evolution of the directly measurable reflectivity and absorption is added. The results of a model calculation for gold are compared with the results of new time-resolved pump-probe-experiments.Auf der Grundlage einer vorangegangenen Arbeit sowie einer linearen Antworttheorie fur hochangeregte Systeme weitab vom Gleichgewicht wird die makroskopische dielektrische Funktion (MDF) mit Hilfe der Dichte-Dichte-Green-Funktion in RPA fur hochangeregte Edelmetallschichten berechnet, wobei die Bandstruktur in grober Naherung berucksichtigt wird. Die Berechnung der zeitlichen Entwicklung des der Messung direkt zuganglichen Reflexionsvermogens und der Absorption wird angeschlossen. Die Resultate einer Modellrechnung fur Gold werden mit Ergebnissentleuerer zeitaufgeloster Pump-Probe-Experimente verglichen.

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The influence of anharmonic renormalization effects on the decay dynamics of coherent longitudinal optical phonons is investigated from a microscopic point of view. Time-resolved coherent anti-Stokes Raman signals are calculated for GaP on the basis of a full phonon dispersion calculation, and the relevant decay channels are identified and compared. Anharmonic renormalization effects are found to induce non-Markovian behaviour of the decay dynamics and lead to a decrease of the decay time. The renormalization effects only depend on the special properties of the phonon dispersion of the given material. This underlines the intrinsic nature of the non-Markovian decay dynamics of phonons for any material. Non-Markovian dynamics of the decay of coherent LO-phonons is calculated for Gap and result in a 30% faster decay signal than the corresponding Markovian dynamics.