Superposition of quantum and classical rotational motions in Sc2C2@C84 fullerite

Author(s)

Karl Michel, Bart Verberck, Martin Hulman, Hans Kuzmany, Mathias Krause

Abstract

The superposition of the quantum rotational motion (tunneling) of the encapsulated Sc2C2 complex with the classical rotational motion of the surrounding C84 molecule in a powder crystal of Sc2C2@C84fullerite is investigated by theory. Since the quantum rotor is dragged along by the C84 molecule, any detection method which couples to the quantum rotor (in casu the C2 bond of the Sc2C2

complex) also probes the thermally excited classical motion (uniaxial

rotational diffusion and stochastic meroaxial jumps) of the surrounding

fullerene. The dynamic rotation-rotation response functions in frequency

space are obtained as convolutions of quantum and classical dynamic

correlation functions. The corresponding Raman scattering laws are

derived, and the overall shape of the spectra and the width of the

resonance lines are studied as functions of temperature. The results of

the theory are confronted with experimental low-frequency Raman spectra

on powder crystals of Sc2C2@C84 [M. Krause et al., Phys. Rev. Lett.93, 137403 (2004)]. The agreement of theory with experiment is very satisfactory in a broad temperature range.

Organisation(s)

Dynamics of Condensed Systems

External organisation(s)

University of Antwerp, Institut für Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden Rossendorf (FZD)

Journal

Journal of Chemical Physics

Volume

126

No. of pages

15

ISSN

0021-9606

DOI

https://doi.org/10.1063/1.2434175

Publication date

2007

Peer reviewed

Yes

Austrian Fields of Science 2012

1030 Physics, Astronomy, 103009 Solid state physics

Portal url

https://ucris.univie.ac.at/portal/en/publications/superposition-of-quantum-and-classical-rotational-motions-in-sc2c2c84-fullerite(0d0c298f-4a91-4a89-a51c-53799aaad413).html