Multipole induced splitting of metal-cage vibrations in crystalline endohedral D2d-M2@C84 dimetallofullerenes.
Metal-carbon cage vibrations of crystalline endohedral D2d-M2@C84 (M=Sc,Y,Dy) dimetallofullerenes were analyzed by temperature dependent Raman scattering and a dynamical force field model. Three groups of metal-carbon cage modes were found at energies of 35-200 cm(-1) and assigned to metal-cage stretching and deformation vibrations. They exhibit a textbook example for the splitting of molecular vibrations in a crystal field. Induced dipole-dipole and quadrupole-quadrupole interactions account quantitatively for the observed mode splitting. Based on the metal-cage vibrational structure it is demonstrated that D2d-Y2@C84 dimetallofullerene retains a monoclinic crystal structure up to 550 K and undergoes a transition from a disordered to an ordered orientational state at a temperature of approximately 150 K.
Institut fur Materialphysik, Universitat Wien, Strudlhofgasse 4, A-1090 Wien, AustriaLeibniz-Institut fur Festkorper- und Werkstofforschung Dresden, Helmholtzstr. 20, 01069 Dresden, Germany.
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Krause
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Popov
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Inakuma
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Tagmatarchis
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Shinohara
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Georgi
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Dunsch
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Kuzmany