Selectivity in the inelastic rotational scattering of hydrogen molecules from graphite

Scattering of N2 Molecules from Silica Surfaces: Effect of Polymorph and Surface Temperature

The inelastic scattering of N₂ molecules from silica surfaces, taken at 100 K, has been investigated by adopting a semiclassical collision model in conjunction with the appropriate treatment of the long-range interaction forces. Such forces promote the formation of the precursor state that controls all basic elementary processes occurring at the gas–surface interphase. The probabilities for the different elementary surface processes triggered by quartz are determined and compared with those recently obtained for another silica polymorph (cristobalite). In addition, the final roto-vibrational distributions of N₂ molecules undergoing inelastic scattering have been characterized. N₂ molecules, impinging on both considered surfaces in low-medium vibrational states, preserve the initial vibrational state, while those inelastically scattered are rotationally excited and translationally colder. The surface temperature effect, investigated by raising the temperature itself from 100 K up to 1000 K, emerges more sharply for the cristobalite polymorph, mainly for the molecules impinging in the ground roto-vibrational state and with low collision energies.

Adsorption of molecular hydrogen on coronene with a new potential energy surface

Adsorption of molecular hydrogen on coronene studied with a new potential energy surface. Path integral Monte Carlo and basin-hopping calculations have been performed to investigate energies and structures of the corresponding (H₂)_N-coronene clusters.