Theoretical prediction that oD₂ spin-echo experiments can measure adsorbate diffusion

³He spin-echo experiments have been used to study adsorbate diffusion, surface phonons, and surface phasons.

Molecular spin-echo experiments proffer the possibility of greater insight into surface dynamics because of the many internal degrees of freedom available, such as rotation.

These many internal degrees of freedom of the molecular probe can significantly complicate the interpretation of spin-echo experiments, however.

We examine the possibility of using a beam of oD₂ molecules to quantitatively measure the diffusion rate of an adsorbate by numerically applying a fully quantum formalism that incorporates both the relevant molecular internal degrees of freedom and the impacts of a dynamic surface on the scattering event.

We demonstrate that despite the complexity of the oD₂ spin-echo signal, data analysis techniques used for ³He spin-echo experiments can be easily modified to analyze oD₂ spin-echo experiments.

We provide multiple such data analysis approaches, allowing for the data analysis method to be chosen according to the conditions of the experiment.

These findings lay the groundwork necessary to interpret spin-echo experiments that study dynamic surfaces with molecular probes.