Global ETD Search
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Showing 1 to 6 of 6 for “"phonon damping"”.
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Real-Time Dynamics of Electrons and Phonons from First Principles
… equation (TDBE) to investigate coupled electron–phonon dynamics in crystalline solids from femtosecond to picosecond timescales. The approach explicitly resolves the dynamics of momentum- and mode-dependent electron and phonon populations, where electron–phonon and phonon–phonon scatterings are …
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Surface phonon polaritons coupled to the far-field by a grating at high temperature
This thesis explores surface phonon polaritons (SPhP) in quartz coupled to the far field by gratings, and the temperature dependence of SPhP coupled to the far field. The subject of coupling SPhP to the far-field has been studied in the past, but not at high temperature. Devices proposed to control …
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Studies of structure and dynamics of biological macro-molecular assemblies by low angle neutron diffraction and inelastic X-ray scattering
… dynamic structure factor measured with IXS, the phonon dispersion relations of 40 wt% calf-thymus Na-DNA with different counterion atmosphere are constructed. It is found that the addition of extra counterions will increase phonon damping at small scattering wave vector, Q. At the intermediate Q …
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Structural dynamics of photoexcited nanolayered perovskites studied by ultrafast x-ray diffraction
… energy from local excitations via delocalized phonon modes of the samples. The complex deformations in tailored multilayers are identified to give rise to highly nonlinear x-ray diffraction responses due to transient interference effects. The understanding of such effects and the ability to …
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Lattice Dynamics in Temperature-driven and Photo-induced Phase Transitions
… the nearly complete measurement of anharmonic phonon behaviors near phase transitions. It is difficult to explain the observed effects of phonon anharmonicity without using first-principles calculations, for instance to obtain renormalized second- order and higher-order force-constants. …
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Spectroscopic perspectives on ultrafast coupling phenomena in perovskite oxides
… I focus on the observation of coherent phonon propagation by time resolved Brillouin scattering: following the excition of metal transducer films with a femtosecond infrared pump pulse, coherent phonon dynamics in the GHz frequency range are triggered. Their propagation is monitored …