Rotor in a Cage: Infrared Spectroscopy of an Endohedral Hydrogen-Fullerene Complex

Abstract

We report the observation of quantized translational and rotational motion of molecular hydrogen inside the cages of C60. Narrow infrared absorption lines at the temperature of 6K correspond to vibrational excitations in combination with translational and rotational excitations and show well resolved splittings due to the coupling between translational and rotational modes of the endohedral H2 molecule. A theoretical model shows that H2 inside C60 is a three-dimensional quantum rotor moving in a nearly spherical potential. The theory provides both the frequencies and the intensities of the observed infrared transitions. Good agreement with the experimental results is obtained by fitting a small number of empirical parameters to describe the confining potential, as well as the ortho to para ratio.

arXiv commentSubmitted to The Journal of Chemical Physics, 4 pages, 2 eps figures

Cited by in corpus (9)

• Interstellar Fullerene Compounds and Diffuse Interstellar Bands
• Infrared spectroscopy of endohedral water in C${}_{60}$
• Infrared spectroscopy of small-molecule endofullerenes
• Encoding many qubits in a rotor
• Near- and Mid-IR Gas-Phase Absorption Spectra of H2@C60+-He
• Algebraic theory of endohedrally confined diatomic molecules: application to H${}_2$@C${}_{60}$
• Exploring the parameter space of an endohedral atom in a cylindrical cavity
• Experimental Determination of the Interaction Potential between a Helium Atom and the Interior Surface of a C60 Fullerene Molecule
• Applications of nuclear physics to a wider context: from molecules to stars passing through hypernuclei