A Non‐Born Oppenheimer Description of Molecular Angular Momentum

ABSTRACT We use variational Monte Carlo methods to optimize fully nonadiabatic trial wavefunctions that describe the J = 0, 1, 2, and 3 rotational states of H 2 + (Ψ 0J ). Our results show that a prefactor that depends on the molecular center of mass yields energies that are in excellent agreement with previous calculations. When we use these trial wavefunctions to evaluate the angular momentum expectation values <Ψ 0J |L 2 |Ψ 0J > and <Ψ 0J |L z |Ψ 0J >, we find that they are eigenfunctions of these operators. We have also evaluated these expectation values for the individual particles in this molecule, and our results show that the electron provides a significant amount of the molecule's angular momentum and that this amount changes for each rotational state.