Resolution and transfer width of thermal energy atomic scattering from solid surfaces TEAS/

The resolution of TEAS has been investigated as a function of energy spread of atomic beam. The model calculations have been executed within the framework of time dependent Schro¨dinger equation. The energy spread of realistic atomic beam has been taken into account by a wave-packet. The wave-packet describes the atomic beam as an ensemble of independent particles by quantum mechanics. Taking ideally periodic surface the resolution of diffraction peaks increases when the energy spread is decreased. This fact underlines the higher efficiency of the supersonic atomic source than the effusive atomic source. Furthermore the transfer width of experimental equipment increases—when the atomic beam monochromaticity is also increased—according to the concept of the transfer width. The relation between the transfer width and the size of the period of the surface topography significantly determines the resolution of the diffraction pattern. q1999 Elsevier Science B.V. All rights reserved