Quantized translational motion of <sup>3</sup>He and <sup>4</sup>He atoms in He@C<sub>60</sub> endofullerene.
ORAL
Abstract
We studied the translational motion of He atom trapped inside the molecular cage of C60 molecule using infrared (IR) spectroscopy. The T dependence of the IR absorption spectra of 3He@C60 and 4He@C60 powder samples was measured between 5 and 300K. At the lowest T a single absorption line was observed at 81 cm-1 (97 cm-1 for 3He), but as the T increased four new lines appeared above the first transition. We fitted the IR spectra with an anharmonic spherical oscillator model and assumed a rigid C60 cage. The line frequencies and intensities were reproduced with the harmonic (V2R2) and anharmonic (V4R4) potential and the induced dipole moment (A1R) terms, where R is the displacement of the He atom from the C60 cage center. The fit gave equal, within the error bars, potential and dipole parameters for 3He@C60 and 4He@C60. The translational energies will be compared to the C60 encapsulated translational energies of H2, HD, D2, HF, and H2O. Our results are the test bed of theories describing the interaction of inert gases with carbon surfaces.
*This research was supported by the institutional research funding IUT23-3 of the Estonian Ministry of Education and Research and the European Regional Development Fund project TK134. We thank EPSRC (UK) and the Royal Society (UK) for support.
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Presenters
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Tanzeeha Jafari
- National Institute of Chemical Physics and Biophysics,Tallinn,Estonia