Non-Born-Oppenheimer MCTDH calculations on the confined H2+ molecular ion

A multiconfiguration time-dependent Hartree method based on non-orthogonal coordinates has been developed. The method has been applied to the calculations of the properties of atomic and molecular systems beyond the Born–Oppenheimer approximation, treating electrons and nuclei on a similar footing. Example calculations have been performed on the confined ion, treated as a genuine three-particle system. With only two orbitals per degree of freedom to begin with, the confinement energy levels as well as the origin of the genuinely bound energy levels have been generated. The initial time evolution of the time-dependent orbitals is also shown.