This book is conceived as a monograph, and represents an up-to-date collection of information concerning the use of the method of X-ray photoelectron spec troscopy in the study of the electron structure of crystals, as well as a personal interpretation of the subject by the authors. In a natural way, the book starts in Chapter 1 with a recapitulation of the fundamentals of the method, basic relations, principles of operation, and a com parative presentation of the characteristics and performances of the most com monly used ESCA instruments (from the classical ones-Varian, McPherson, Hewlett Packard, and IEEE-up to the latest model developed by Professor Siegbahn in Uppsala), and continues with a discussion of some of the difficult problems the experimentalist must face such as calibration of spectra, prepara tion of samples, and evaluation of the escape depth of electrons. The second chapter is devoted to the theory of photoemission from crystal line solids. A discussion of the methods of Hartree-Fock and Hartree-Fock Slater for the calculation of bonding energy levels in multielectronic systems is presented, and the necessity of including in the theory both relativistic and relaxation effects is argued.
