Computational Energy Spectra of the H₂ O@C₇₀ Endofullerene

A water molecule confined inside the C₇₀ fullerene was quantum-mechanically described using a computational approach within the MCTDH framework. Such procedure involves the development of a full-dimensional coupled hamiltonian, with an exact kinetic energy operator, including all rotational, translational and vibrational degrees of freedom of the endofullerene system. In turn, through an effective pairwise potential model, the ground and rotationally excited states of the encapsulated H₂ O inside the C₇₀ cage were calculated, and traced back to the isotropic case of the H₂ O@C₆₀ endofullerene in order to understand the nature and physical origin of the symmetry breaking observed experimentally in the latter system. Moreover, the computational scheme used here allows to study the quantization of the translational movement of the encapsulated water molecule inside the C₇₀ fullerene, and to investigate the confinement effects in the vibrational energy levels of the H₂ O@C₇₀ system.