Empirical Determination\nof Scattering Matrices from\nMagnetic Molecular Interferometry for Gas–Surface Collisions

The rotational orientation dependence of H<sub>2</sub> scattering\ninto different diffraction channels on a Cu(511) surface is studied\nusing a magnetic manipulation interferometry technique. For some channels,\nmarkedly different signals are measured, whereas for others, they\nare more similar. The data are analyzed to obtain scattering matrices,\nwhich quantify how the amplitude and phase of the wave function change\nduring the gas–surface collision and are extremely sensitive\nto the underlying potential. Fits to simulated data with noise at\nlevels comparable to those obtained in the experimental data are also\npresented, which provide an estimate of the error on the scattering\nmatrix parameters that are\nobtained, with the uncertainties in the values tending to be lower\nfor the higher order diffraction peaks. The results presented here\nprovide extremely stringent benchmarks for the development of accurate\ntheoretical models, with the number of different channels studied\nreducing the likelihood of an inaccurate model fortuitously reproducing\nall the data.