Computational Energy Spectra of the H2O@C70 Endofullerene

A water molecule confined inside the C-70 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 H2O inside the C-70 cage were calculated, and traced back to the isotropic case of the H2O@C-60 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 C-70 fullerene, and to investigate the confinement effects in the vibrational energy levels of the H2O@C-70 system.