Communication: Quantum six-dimensional calculations of the coupled translation-rotation eigenstates of H2O@C60.

We report rigorous quantum calculations of the translation-rotation (TR) eigenstates of para- and ortho-H₂O@C₆₀. They provide a comprehensive description of the dynamical behavior of H₂O inside the fullerene having icosahedral (Ih) symmetry. The TR eigenstates are assigned in terms of the irreducible representations of the proper symmetry group of H₂O@C₆₀, as well as the appropriate translational and rotational quantum numbers. The coupling between the orbital and the rotational angular momenta of the caged H₂O gives rise to the total angular momentum λ, which additionally labels each TR level. The calculated TR levels allow tentative assignments of a number of transitions in the recent experimental INS spectra of H₂O@C₆₀ that have not been assigned previously. [ABSTRACT FROM AUTHOR]