The development of linear-scaling density functional theory (LS-DFT) has made ab initio calculations on systems containing thousands of atoms possible. These systems range from nanostructures to biomolecules. These methods rely on the use of localized basis sets, which are optimised for the representation of occupied Kohn-Sham states but do not guarantee an accurate representation of the unoccupied states. This is problematic if one wishes to combine the power of LS-DFT with that of theoretical spectroscopy, which provides a direct link between simulation and experiment. In this work a new method is presented for optimizing localized functions to accurately represent the unoccupied states, thus allowing theoretical spectroscopy of large systems. Results are presented for optical absorption spectra calculated using the ONETEP code, but the method is equally applicable to other spectroscopies and LS formulations. Other topics covered include a study of some simple one dimensional basis sets and the presentation of two methods for band structure calculation using localized basis sets, both of which have important implications for the use of localized basis sets within LS-DFT.

http://www.worldscientific.com/worldscibooks/10.1142/0111

Neutron radiography has in recent years emerged as a useful and complementary technology for radiation diagnosis. It is now routinely used in industrial quality assurance and in support of selected research and developmental activities. Conferences are held on the subject, pertinent handbooks exist, and technical papers appear regularly reporting on new developments. While neutron radiography has indeed passed through the transition from a scientific curiosity to technological relevance, it is a sign of its continuing dynamic evolution that little material has appeared which provides an integrated mathematical and physical analysis of the subject possessing both an instructional as well as reference function. It is our hope that this monograph will fill this need. The distinctiveness of neutron radiography rests on the unique interactions between neutrons and nuclei. This leads to some special relationships between the material and geometrical properties of an object and the neutron radiographic image. The evolution of a technical discipline demands that specific conceptual constructs be developed and their mathematical representations examined and compared with controlled experiments. Experience has convinced us that a particular and substantial body of knowledge has accumulated endowing neutron radiography with the essential foundations of a unique mathematical and physical science. Our scientific and professional involvement in neutron radiography began some 15 years ago when the senior author (A.A.H.) found himself with convenient access to the McMaster University Nuclear Reactor and research support from the Government of Canada.

The motivations, goals and general culture of theoretical physics and mathematics are different. Most practitioners of either discipline have no necessity for most of the time to keep abreast of the latest developments in the other. However on occasion newly developed mathematical concepts become relevant in theoretical physics and the less rigorous theoretical physics framework may prove valuable in understanding and suggesting new theorems and approaches in pure mathematics. Such interdis ciplinary successes invariably cause much rejoicing, as over a prodigal son returned. In recent years the framework provided by quantum field theory and functional in tegrals, developed over half a century in theoretical physics, have proved a fertile soil for developments in low dimensional topology and especially knot theory. Given this background it was particularly pleasing that NATO was able to generously sup port an Advanced Research Workshop to be held in Cambridge, England from 6th to 12th September 1992 with the title Low Dimensional Topology and Quantum Field Theory. Although independently organised this overlapped as far as some speak ers were concerned with a longer term programme with the same title organised by Professor M Green, Professor E Corrigan and Dr R Lickorish. The contents of this proceedings of the workshop demonstrate the breadth of topics now of interest on the interface between theoretical physics and mathematics as well as the sophistication of the mathematical tools required in current theoretical physics."

More than 50 years ago, in 1934, Chadwick and Goldhaber (ChG 34) published a paper entitled "A 'Nuclear Photo-effect' Disintegration of the Diplon by -y-Rays."l in the introduction: They noted "By analogy with the excitation and ionisation of atoms by light, one might expect that any complex nucleus should be excited or 'ionised', that is, disintegrated, by -y-rays of suitable energy," and furthermore: "Heavy hydrogen was chosen as the element first to be examined, because the diplon has a small mass defect and also because it is the simplest of all nuclear systems and its properties are as important in nuclear theory as the hydrogen is in atomic theory." Almost at the same time, in 1935, the first theoretical paper on the photodisinte gration of the deuteron entitled "Quantum theory of the diplon" by Bethe and Peierls (BeP 35) appeared. It is not without significance that these two papers mark the be ginning of photonuclear physics in general and emphasize in particular the special role the two-body system has played in nuclear physics since then and still plays. A steady flow of experimental and theoretical papers on deuteron photo disintegration and its inverse reaction, n-p capture, shows the continuing interest in this fundamental process (see fig. 1.1)."

The papers collected in this volume have been presented during a workshop on "Electron-Atom and Molecule Collisions" held at the Centre for Interdisciplinary Studies of the University of Bielefeld in May 1980. This workshop, part of a larger program concerned with the "Properties and Reactions of Isolated Molecules and Atoms," focused on the theory and computational techniques for the quanti tative description of electron scattering phenomena. With the advances which have been made in the accurate quantum mechanical characterisation of bound states of atoms and molecules, the more complicated description of the unbound systems and resonances important in electron collision processes has matured too. As expli cated in detail in the articles of this volume, the theory for the quantitative explanation of elastic and inelastic electron molecule collisions, of photo- and multiple photon ionization and even for electron impact ionization is well developed in a form which lends itself to a complete quantitative ab initio interpretation and pre diction of the observable effects. Many of the experiences gained and the techniques which have evolved over the years in the com putational characterization of bound states have become an essential basis for this development. To be sure, much needs to be done before we have a complete and detailed theoretical understanding of the known collisional processes and of the phenomena and effects, which may still be un covered with the continuing refinement of the experimental tech niques."

The work presented in this book is a major step towards understanding and eventually suppressing background in the direct search for dark matter particles scattering off germanium detectors. Although the flux of cosmic muons is reduced by many orders of magnitude in underground laboratories, the remaining energetic muons induce neutrons through various processes, neutrons that can potentially mimic a dark matter signal. This thesis describes the measurement of muon-induced neutrons over more than 3 years in the Modane underground laboratory. The data are complemented by a thorough modeling of the neutron signal using the GEANT4 simulation package, demonstrating the appropriateness of this tool to model these rare processes. As a result, a precise neutron production yield can be presented. Thus, future underground experiments will be able to reliably model the expected rate of muon-induced neutrons, making it possible to develop the necessary shielding concept to suppress this background component.

By providing the reader with a foundational background in high spin nuclear structure physics and exploring exciting current discoveries in the field, this book presents new phenomena in a clear and compelling way. The quest for achieving the highest spin states has resulted in some remarkable successes which this monograph will address in comprehensive detail. The text covers an array of pertinent subject matter, including the rotational alignment and bandcrossings, magnetic rotation, triaxial strong deformation and wobbling motion and chirality in nuclei. This book offers a clearly-written and up-to-date treatment of the topics covered. The prerequisites for a proper appreciation are courses in nuclear physics and nuclear models and measurement techniques of observables like gamma-ray energies, intensities, multi-fold coincidences, angular correlations or distributions, linear polarization, internal conversion coefficients, short lifetime (pico-second range) of excited states etc. and instrumentation and data analysis methods.

Introducing the basic theory and recent advances in QCD, this book reviews the historical development of the subject up to the present day, covering aspects of strong interactions such as the quark and parton models, the notion of colors and the S-matrix approach. The author then discusses QCD and QED as gauge theories, renormalization procedures, QCD hard processes in hadron collisions, hadron jets, and the different non-perturbative aspects of QCD.

Writing even in overview of more than a half-century of professional life of a giant of twentieth century science and technology such as Edward Teller is a daunting task. We ask in advance the reader's pardon for passing over quickly or omitting entirely aspects of Teller's life and work which may seem of major significance but which we, due to differences of perspective or knowledge, speak too little or not at all. We refer those interested in greater depth to the excellent biography by Stanley Blumberg and Gwen Owens, The Life and Times of Edward Teller, and we have (with his permission) printed Professor Eugene Wigner's An Appreciation On the 60th Birthday of Edward Teller immediately after this foreword, so that the reader may consider the perspective of one of Teller's most illustrious contemporaries more than two decades ago. Edward Teller was born in Budapest, Hungary on January 15,1908. While his childhood was spent in the twilight of the Victorian age and its abrupt conclusion in the Great War and his youth in its especially turbulent after math in central Europe, he doesn't bear visible scars from it."

In the50years since the first volume of "Progress in Optics" was published, optics has become one of the most dynamic fields of science. The volumes in this series that have appeared up to now contain more than 300 review articles by distinguished research workers, which have become permanent records for many important developments, helping optical scientists and optical engineers stay abreast of their fields.
Comprehensive, in-depth reviewsEdited by the leading authority in the field"

Experts on elementary-particle physics, both theorists and experimentalists, met to present their latest results on the various aspects of HERA physics, specifically, the H1 and ZEUS collaborations at HERA and the collaborations at LEP and the Tevatron were presented. The topics included: proton structure function; polarized "ep" scattering; final states in deep-inelastic scattering (DIS), with special emphasis on jet production at low x, power corrections in DIS, soft particle production, and instanton effects; photon structure function; photoproduction of jets and hadrons; heavy-flavour and charmonium production; elastic and diffractive ep scattering; and new physics at HERA.

Stars are born and die in clouds of gas and dust, opaque to most types of radiation, but transparent in the infrared. Requiring complex detectors, space missions and cooled telescopes, infrared astronomy is the last branch of this discipline to come of age. After a very successful sky survey performed in the eighties by the IRAS satellite, the Infrared Space Observatory, in the nineties, brought spectacular advances in the understanding of the processes giving rise to powerful infrared emission by a great variety of celestial sources.

Outstanding results have been obtained on the bright comet Hale-Bopp, and in particular of its water spectrum, as well as on the formation, chemistry and dynamics of planetary objects in the solar system. Ideas on the early stages of stellar formation and on the stellar initial mass function have been clarified.

ISO is the first facility in space able to provide a systematic diagnosis of the physical phenomena and the chemistry in the close environment of pre-main sequence stars, in the interstellar medium, and in the final stages of stellar life, using, among other indicators, molecular hydrogen, ubiquitous crystalline silicates, water and ices.

ISO has dramatically increased our ability to investigate the power production, excitation and fuelling mechanism of galaxies of every type, and has discovered a new very cold dust component in galaxies.

ISO has demonstrated that luminous infrared galaxies were brighter and much more numerous in the past, and that they played a dominant role in shaping present day galaxies and in producing the cosmic infrared background.

The three articles of the present volume pertain to very different subjects, all ofconsiderable current interest. The first reviews the fascinating history ofthe search for nucleon substructure in the nucleus using the strength ofGamow- Teller excitations. The second deals with deep inelastic lepton scattering as a probe ofthe non-perturbative structure of the nucleon. The third describes the present state ofaffairs for muon catalyzed fusion, an application of nuclear physics which many new experiments have helped to elucidate. This volume certainly illustrates the broad range ofphysics within our field. The article on Nucleon Charge-Exchange Reactions at Intermediate Energy, by Parker Alford and Brian Spicer, reviews recent data which has clarified one of the greatest puzzles of nuclear physics during the past two decades, namely, the "missing strength" in Gamow-Teller (GT) transitions. The nucleon-nucleon interaction contains a GT component which has a low-lying giant resonance. The integrated GT strength is subject to a GT sum rule. Early experiments with (n, p) charge exchange reactions found only about half of the strength, required by the sum rule, in the vicinity of the giant resonance. At the time, new theoretical ideas suggested that the GT strength was especially sensitive to renormalization from effects pertaining to nucleon substructure, particularly the delta excitation of the nucleon in the nucleus.

This book introduces the reader to the use of Monte Carlo methods for solving practical problems in radiation transport, and will also serve as a reference work for practitioners in the field. It assumes the reader has a general knowledge of calculus and radiation physics, and a knowledge of Fortran programming, but assumes no prior knowledge of stochastic methods or statistical physics. The subject is presented by a combination of theoretical development and practical calculations. Because Monte Carlo methods are closely linked to the use of computers, from the beginning the reader is taught to convert the theoretical constructs developed in the text into functional software for use on a personal computer. Example problems provide the reader with an in-depth understanding of the concepts presented and lead to the production of a unique learning tool, a probabilistic framework code that models in a simple manner the features of production of Monte Carlo transport codes. This framework code is developed in stages such that every function is understood, tested, and demonstrated - random sampling, generating random numbers, implementing geometric models, using variance reduction, tracking particles in a random walk, testing the thoroughness with which the problem phase space is sampled, scoring detectors, and obtaining estimates of uncertainty in results. Advanced topics covered include criticality, correlated sampling, adjoint transport, and neutron thermalization. Monte Carlo codes can produce highly precise wrong answers. The probability of this occurring is increased if production codes are run as opaque, black boxes' of software. This text attempts to make Monte Carlo into acomprehensible, usable tool for solving practical transport problems. It is suitable for advanced undergraduate and graduate students and researchers who wish to expand their knowledge of the Monte Carlo technique.

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Combining incisive experiments with the latest theoretical advances, this book presents an extensive study of transfer-triggered breakup, the dominant process by which breakup occurs in reactions involving light, weakly bound nuclei. It demonstrates not only that lifetimes of resonant states shorter than a zeptosecond are crucially important for these reactions to suppress complete fusion, but also that such short lifetimes are experimentally accessible. By making quantitative predictions of the effect of breakup from short-lived resonant states on incomplete fusion at above-barrier energies, the book suggests that the extent to which near-target breakup can suppress complete fusion is much more limited than previously thought. With an impressive amount of complex data and state-of-the-art models, which were developed, modified, and tested over course of the Ph.D., it examines all aspects of nuclear reactions - nuclear models, modern detectors and spectrometers, as well as data analysis, and offers a detailed discussion of experimental results and technical developments like new radioactive beams. This excellent and beautifully written book presents outstanding quality experimental work that establishes a cornerstone in our understanding of the reaction dynamics of light weakly bound nuclei at energies around the Coulomb barrier.

This monograph recounts and details the development of a nuclear rocket engine reactor (NRER). In particular, it explains the working capacity of an active zone NRER under mechanical and thermal load, intensive neutron fluxes, and high-energy generation (up to 30 MBT/l) in a working medium (hydrogen) at temperatures up to 3100 K. The design principles and bearing capacity of reactors area discussed on the basis of simulation experiments and test data of a prototype reactor. Property data of dense constructional, porous thermal insulating and fuel materials such as carbide and uranium carbide compounds in the temperatures interval 300 - 3000 K are presented.; technological aspects of strength and thermal strength resistance of materials are also considered. As well, a procedure to design possible emergency processes in the NRER is developed and risks for their origination are evaluated. Finally, prospects for use in pilotless space devices and piloted interplanetary ships are reviewed.