Setting benchmarks for modelling gas–surface interactions using coherent control of rotational orientation states
Yosef Alkoby, Helen Chadwick, O. Godsi, Hamza Labiad, Matthew Bergin, Joshua T. Cantin, I. Litvin, T. Maniv, Gil Alexandrowicz
Abstract
Abstract The coherent evolution of a molecular quantum state during a molecule-surface collision is a detailed descriptor of the interaction potential which was so far inaccessible to measurements. Here we use a magnetically controlled molecular beam technique to study the collision of rotationally oriented ground state hydrogen molecules with a lithium fluoride surface. The coherent control nature of the technique allows us to measure the changes in the complex amplitudes of the rotational projection quantum states, and express them using a scattering matrix formalism. The quantum state-to-state transition probabilities we extract reveal a strong dependency of the molecule-surface interaction on the rotational orientation of the molecules, and a remarkably high probability of the collision flipping the rotational orientation. The scattering matrix we obtain from the experimental data delivers an ultra-sensitive benchmark for theory to reproduce, guiding the development of accurate theoretical models for the interaction of H 2 with a solid surface.