Scattering Distribution Characteristics of Rare Gases Reflected from Metal Surface with Absorbed Gas Molecules

摘要

Reflected intensity distributions of neon, argon and krypton from planes of silver, nickel and platinum were measured at incident energies ranging from 0.06 to 3.8 eV. The surfaces of these metals were assumed to be contaminated by absorbed molecules as no effort was made to remove them. Lobular patterns were obtained for nickel and platinum planes when the incident energies exceeded 1.0 eV. For silver planes, the distribution pattern was always lobular even when the incident energies were low. For these lobular distributions, the behavior of two characteristics, delta theta, the deviation of the angle of the maximum flux from the specular direction and lambda, the width at half height, was studied and compared with existing results obtained from clean surfaces. With the presence of adsorbed molecules, distribution profiles compared with those of clean surfaces become broader and the direction of the maximum flux moves towards the surface normal. From precise studies of the characteristics, it could be concluded that, in the scattering, the adsorbed layer works to reduce the incident energies and raise the surface temperature by absorbing the incident energies. When the incident energies become high, sputtering of adsorbed molecules begins to occur and the measured patterns gradually approach those of clean surfaces.