Surface Excitation Probabilities In Surface Electron Spectroscopies And Monte Carlo Simulation Of Electron-Solid Interactions

The phenomenon of surface excitation is competitive in nature for elastic and other inelastic scattering processes in surface electron spectroscopies; the knowledge of influence of surface excitations in electron energy loss spectra is then essential for quantitative surface analysis with these spectroscopies. In this thesis, the inelastic scattering of electron moving in the vicinity of surface is studied in the frame work of complex self energy of electron. The formalism is based on quantum mechanical treatment of interaction of electrons with semi-infinite medium which uses the optical bulk dielectric function. The imaginary part of the complex self energy of electron provides spatial and angular dependent differential inverse inelastic mean free path (DIIMFP). The contribution of surface excitation in electron-solid interactions is estimated via the numerical evaluation of total surface excitation probability, known as surface excitation parameter (SEP). Two different methods were employed to verify the computed SEP by Monte Carlo simulation of electron-solid interactions. The thesis consists of following eight chapters.Chapter One describes the general concepts related to the phenomena of electron-surface and electron-solid interactions in the context of electron spectroscopy and Monte Carlo simulation.Chapter Two explains the theoretical modeling for electron transport in solids through electron elastic and inelastic interactions. The problem of electron inelastic interaction with the medium is treated through a complex function called self energy of electron.Chapter Three provides the outline for the procedure for Monte Carlo simulation adopted for electron elastic and inelastic interaction in order to simulate electron interaction phenomena in solids and at surfaces.Chapter Four describes important aspects of the extended modeling of interaction of electrons with a semi-infinite medium in order to obtain the formulation for the total surface excitation probability, i.e., the so called SEP. The SEP is obtained by integrating the surface term of DIIMFP over energy loss and depth. The kinetic energy range of probing electrons considered is 100-5000 eV and the numerical computation of total surface excitation probabilities are performed for several metals, Au, Ag, Cu, Ni, Fe and Ti. An empirical formulae as a function of energy and angle for the surface excitation probability are given for each of these materials...