Collective electronic excitations in carbon fullerene clusters
نویسنده
چکیده
Recent theoretical results for the response of Czo , CGO and C70 fnllerene clusters to external electromagnetic fields are reviewed. The calculated static response of free eGO has large linear and nonlinear components, the latter being much smaller than originally suggested and significantly reduced by screening effects. Random field approximation calculations indicate that the dynamical dipole response of Czo , CGO and C70 is characterized by two strongly collective modes, namely a Mie-type ,,-plasmon at hw:::::20 eV, and a Jr-plasmon at hw:::::6 eV. These modes also dominate the response of these systems to multipolar external fields and hence the electron energy loss spectra. The large oscillator strength of these modes is collected from lower-lying particle-hole excitations which consequently experience strong dynamical screening. Typeset using REVTEX
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