Adsorption and Diffusion Behavior of Xe/Kr Gas on Al₂O₃ and Stilbene Surface

The adsorption and diffusion behavior of radioactive inert gases, xenon (Xe) and krypton (Kr), on flat and rough surfaces of Al₂O₃ and stilbene, were investigated using molecular dynamics (MD) simulations based on the compass force field. The diffusion coefficients of Xe/Kr were determined from the root mean square displacement (MSD) of the inert gas adsorption curves. The results indicate that Xe/Kr gas can stably adsorb on the Al₂O₃ and stilbene surface, and the Xe’s adsorption is stronger than Kr’s on both surfaces. The adsorption energies increase with the thickness of the stilbene substrate, whereas they decrease for the Al₂O₃ substrate. The inert gases’ adsorption performance and diffusion coefficient on rough stilbene surfaces are significantly increased; however, the surface roughness has little effect on the Al₂O₃ adsorption performance. The study can guide the design of highly sensitive scintillators with low backgrounds.