MONTE-CARLO SIMULATION OF ANGULAR-SCAN SPECTRA FOR COAXIAL IMPACT COLLISION ION-SCATTERING SPECTROSCOPY (CAICISS)

The concept of the close-encounter probability was applied to simulate the angle-dependent surface peak intensities in coaxial impact collis ion ion scattering spectroscopy (CAICISS). It needs to follow incident trajectories only from a top surface up to several tens of monolayers below a surface and reduces the computing time remarkably. The simula tion was performed for a polar-scan spectrum for TiO2-terminated SrTiO 3(001) using 3 keV He+ beams incident upon its (100) plane. This metho d reproduced well the observed polar-scan spectrum for Sr peak intensi ties except for grazing incidence less than 30 degrees. On the other h and, the Williams' method, which has been frequently utilized, gave pr onounced deviation due to neglect of the contributions from the depths . The applicability and limitation of the present method is discussed in detail.