33 research outputs found

    Mass Renormalization in the Su-Schrieffer-Heeger Model

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    This study of the one dimensional Su-Schrieffer-Heeger model in a weak coupling perturbative regime points out the effective mass behavior as a function of the adiabatic parameter ωπ/J\omega_{\pi}/J, ωπ\omega_{\pi} is the zone boundary phonon energy and JJ is the electron band hopping integral. Computation of low order diagrams shows that two phonons scattering processes become appreciable in the intermediate regime in which zone boundary phonons energetically compete with band electrons. Consistently, in the intermediate (and also moderately antiadiabatic) range the relevant mass renormalization signals the onset of a polaronic crossover whereas the electrons are essentially undressed in the fully adiabatic and antiadiabatic systems. The effective mass is roughly twice as much the bare band value in the intermediate regime while an abrupt increase (mainly related to the peculiar 1D dispersion relations) is obtained at ωπ2J\omega_{\pi}\sim \sqrt{2}J.Comment: To be published in Phys.Rev.B - 3 figure

    Singlet oxygen luminescence detecting in presence of hybrid associates of colloidal Ag

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    In our work we demonstrate some spectroscopic investigation of colloidal Ag2S QDs associates with methylene blue. The photosensitizing of singlet oxygen by associates of colloidal Ag2S QDs with methylene blue was found

    Singlet oxygen luminescence detecting in presence of hybrid associates of colloidal Ag2S quantum dots with methylene blue molecules

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    In our work we demonstrate some spectroscopic investigation of colloidal Ag2S QDs associates with methylene blue. The photosensitizing of singlet oxygen by associates of colloidal Ag2S QDs with methylene blue was found
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