Towards the end of the 1960s, a number of quite different circumstances combined to launch a period of intense activity in the digital processing of electron micro graphs. First, many years of work on correcting the resolution-limiting aberrations of electron microscope objectives had shown that these optical impediments to very high resolution could indeed be overcome, but only at the cost of immense exper imental difficulty; thanks largely to the theoretical work of K. -J. Hanszen and his colleagues and to the experimental work of F. Thon, the notions of transfer func tions were beginning...

The suggestion by Dr. Franklin S. Harris, Jr., that these books be written arose pursuant to the editor's plaints that despite the implicitly or explicitly ack nowledged importance of both aerosols and particulate matter in innumerable domains of technology and human welfare, investigations of these subjects were generally not supported independently of the narrowest conceivable domains of their appli cations. Frank Harris, who has long been a contributor in one of the important domains of aerosol macrophysics, atmospheric optics, challenged the editor to elaborate his views. Ideally, they...

The theory of the chemical interaction of molecules with surfaces has advanced handsomely in the last few years. This is due in part to the application of the entire arsenal of bulk solid-state theory and molecular quantum chemistry methods. This considerable activity was stimulated by an outpouring of experimental data, particularly of photoemission spectra. In many cases the theoretical techniques are now such that accurate, atomistic pictures of chemisorption phenomena are computed from first principles. This level of capability has been reached only recently, and has not been described...

Until the beginning of this decade the number of significant exactly soluble problems in physics was limited to a very few: the classical or quanti sed harmonic oscillator, the linearised many-body problem, the quanti sed hydrogen atom, Newton's solution of the planetary orbit problem, Onsager's solution of the two-dimensional Ising problem, almost exhaust the list. Now the situation is quite different. We have a large number of exactly soluble nonlinear systems of physical significance and the number of these is growing steadily. Recent examples include a limited solution of Ein- stein's...

When, in the spring of 1979, H.P. Baltes presented me with the precursor of this vo 1 ume, the book on "Inverse Source Problems in Opti cs", I expressed my gratitude in a short note, 11hich in translation, reads: "Dear Dr. Ba ltes, the mere titl e of your unexpected gift evokes memori es of a period, which, in the terminology of your own contribution, would be described as the Stone Age of the Inverse Problem. Those were pleasant times. Walter Kohn and I lived in a cave by ourselves, drew pictures on the walls, and nobody seemed to care. Now, however, Inversion has become an Industry, which I...

No single volume has been entirely devoted to the properties of magnetic lenses, so far as I am aware, although of course all the numerous textbooks on electron optics devote space to them. The absence of such a volume, bringing together in formation about the theory and practical design of these lenses, is surprising, for their introduction some fifty years ago has created an entirely new family of commercial instruments, ranging from the now traditional transmission electron microscope, through the reflection and transmission scanning microscopes, to co lumns for micromachining and...

The growth and maturity of research in structural phase transitions (SPT) make it an appropriate subject for the Topics in Current Physics series. The maturing pro- cess is, however, by no means complete. New areas such as incommensurable SPT, quasi-low-dimensional systems, systems containing lattice disorder due to impuri- ties or as mixed crystals, multicritical points, and quantum effects have recently come under focus. The understanding of the dynamics, be it microscopic soft-mode theory or critical dynamics, more specifically the central-peak problem, is also still quite incomplete. On...

It is now ten years since it was first convincingly shown that below 1 K the ther mal conductivity and the heat capacity of amorphous solids behave in a way which is strikingly different to that of crystalline solids. Since that time there has been a wide variety of experimental and theoretical studies which have not only defined and clarified the low temperature problem more closely, but have also linked these differences between amorphous and crystalline solids to those suggested by older acoustic and thermal experiments (extending up to 100 K). The interest in this somewhat restricted...

With the advent of X-ray diffraction and crystal structure determination in 1912 researchers in physics and chemistry began investigating the problem of crystal co hesion, i. e., on the question of what holds crystals together. The names of M. Born, E. Madelung, P. P. Ewald, F. Bloch, E. P. Wigner, and J. E. Mayer are, in particular, associated with the pre-1940 work on the cohesion of inorganic lattices. The advent of digital computers brought along great advances in the detailed understanding of ionic crystals, molecular crystals, and metals. The work of P. O. Lowdin and r A. I....