H ₂ Vibrations in a Spherical Potential Well

The internal and librational and vibrational modes of an H 2 molecule in a spherical potential energy well are investigated. This system provides an efficient ansatz for the modeling spectroscopic properties of H 2 molecules in applications like hydrogen storage into fullerenes or into the smaller cages of sII‐type clathrates. The potential energy surface, obtained by quantum diffusion Monte Carlo calculations, is fed into the nuclear dynamics through a multilayer neural network, which provides a convenient solution to the statistical scatter intrinsic to Monte Carlo calculations. Wavenumbers for all three vibrational modes are calculated for a well size suitable to emulate H 2 @C 20 , showing the effect of nanoconfinement.