Showing papers in "Reports on Progress in Physics in 1974"
TL;DR: In this article, a detailed discussion of the properties of bulk polaritons in an isotropic dielectric, with a single infrared active optical phonon is given, and the phonon and photon strength functions, which provide a useful means of characterizing the polariton are introduced.
Abstract: A detailed discussion of the properties of bulk polaritons in an isotropic dielectric, with a single infrared active optical phonon is given. The phonon and photon strength functions, which provide a useful means of characterizing the polariton are introduced, and polaritons examined in magnetic crystals, anisotropic dielectrics, materials in which spatial dispersion effects and absorption are important. Experimental methods of studying polaritons are reviewed, with emphasis on Raman scattering, non-linear interactions between polaritons and recent experimental studies of non-linear optical phenomena where polaritons in the intermediate state play an important role. The properties of surface polaritons at the interfaces of the isotropic dielectric, anisotropic dielectrics and magnetic media, and experimental methods for the study of surface polaritons are also discussed. The paper concludes with the comparison between the properties of coupled magnon-phonon modes in magnetic crystals and polaritons.
416 citations
TL;DR: A detailed review of the principles governing the oxidation of metals is presented in this paper, which covers the initial stages of oxidation, oxide film formation, thick film and scale formation and oxide structure.
Abstract: A detailed review of the principles governing the oxidation of metals is presented. It covers the initial stages of oxidation, oxide film formation, thick film and scale formation and oxide structure.
322 citations
TL;DR: In this paper, the properties of 3D transition metal impurities in simple metal hosts are summarized and a short discussion of the basic microscopic models, then the Anderson model is treated in some detail.
Abstract: The properties of 3d transition metal impurities in simple metal hosts are summarized. There is a short discussion of the basic microscopic models, then the Anderson model is treated in some detail. The next section considers the s-d model and the Kondo effect. The main experimental features are reviewed and finally the question of dilute alloys is considered.
255 citations
TL;DR: In this article, a brief discussion of the assumptions, accuracy and precision of 'geological' errors present in physical geochronometry is presented. And five major physical methods of rock and mineral age determinations currently in use, are described.
Abstract: Presents a brief discussion of the assumptions, accuracy and precision of 'geological' errors present in physical geochronometry. The five major physical methods of rock and mineral age determinations currently in use, are described.
249 citations
TL;DR: In this paper, most of the experimental data which have been obtained from measurements of bulk properties of alloys and intermetallic compounds containing atoms of transition metals, rare earths or actinides which can be considered as noninteracting with each other are given.
Abstract: This review presents systematically most of the experimental data which have been obtained from measurements of bulk properties of alloys and intermetallic compounds containing atoms of transition metals, rare earths or actinides which can be considered as non-interacting with each other. Criteria for the observation of effects due to non-interacting atoms are given. Data are reported from measurements of magnetic properties, electrical resistivity, specific heat, superconductivity, thermoelectric power, thermal conductivity, thermal expansion and compressibility, de Haas-van Alphen and Hall effects and optical properties. Systematic trends in experimental behaviour can be observed in many of these data, and using this observation experimental parameters are defined which are used to classify the data before attempting a comparison with theories.
185 citations
TL;DR: The theory of the electronic states of crystals containing point defects in small concentration is reviewed and its application to the case of semiconductors is discussed in this paper, making use of the effective mass approximation and taking into account interband mixing and central cell corrections.
Abstract: The theory of the electronic states of crystals containing point defects in small concentration is reviewed and its application to the case of semiconductors is discussed. The basic properties of scattering and resonant and bound states are related to the band structure of the semiconductor. The form of the impurity potentials and the effect of the dielectric screening and deep levels are also discussed. Applications to the cases of donor acceptor and isoelectronic impurities are described, making use of the effective mass approximation and taking into account interband mixing and central cell corrections. Existing calculations are reviewed and compared with some of the experimentally known levels. Optical processes involving transitions between all types of electronic levels are described and experimental evidence for them is reported. Effects of external perturbations like uniaxial pressure, electric and magnetic fields are finally examined.
154 citations
TL;DR: In this paper, the Glauber amplitude formula has been applied to elastic and inelastic collisions of charged particles with neutral atoms, both for potential scattering and for composite collisions, and a number of possible problems for future research are listed.
Abstract: Applications of the Glauber approximation to elastic and inelastic collisions of charged particles with neutral atoms are critically reviewed in an attempt to assess the utility of the Glauber approximation in the atomic collisions domain. Various alternative derivations of the Glauber amplitude formula, both for potential scattering and for composite collisions, also are described and compared. A number of possible problems for future research are listed.
120 citations
TL;DR: In this paper, a review of the attempts to obtain a quantum theory of gravitation is presented, and the essential ideas of those programmes on which extensive work has been done are discussed.
Abstract: Attempts to obtain a quantum theory of gravitation are reviewed. The essential ideas of those programmes on which extensive work has been done are discussed. Successes and difficulties of each of these programmes are described. The attempts are divided into two broad classes: those based on the techniques of canonical quantization and those based on the techniques of quantum field theory. The authors approach is rather geometrical, an approach which facilitates the comparison of various programmes.
102 citations
TL;DR: In this paper, a review is devoted to low temperature methods of the study of electron scattering on phonons in metals, and the basic emphasis is put on those experiments or those aspects of experiments which are governed by or can yield information about the electron-phonon scattering anisotropy.
Abstract: The review is devoted to low temperature methods of the study of electron scattering on phonons in metals. The basic emphasis is put on those experiments or those aspects of experiments which are governed by or can yield information about the electron-phonon scattering anisotropy, i.e. the dependence of scattering probability on the electron position on the Fermi surface.
87 citations
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TL;DR: In this article, the authors present a review of the advances in understanding the basic processes of ion beam systems with the objective of indicating the advances that are important for ion beam applications.
Abstract: In recent years the requirements for higher current ion beams have increased notably in a wide area of applications. To meet these requirements it has been necessary to develop better understanding of the three main components of ion beam systems, namely the plasma source in which ions of the species needed can be produced at controlled rates with spatial and temporal uniformity, the extraction electrode systems for formation of low divergence and low emittance ion beams, and the transport of the ion beams in the presence of possible high space charge forces. In this review developments in these areas are discussed with the objective of indicating the advances in understanding the basic processes which are important.
87 citations
TL;DR: In this paper, the authors considered silicon and gallium arsenide as typical examples of elemental and compound semiconductors respectively, and an account is given of the nucleation, growth and structure of autoepitaxial films of these materials.
Abstract: In this review silicon and gallium arsenide are considered as typical examples of elemental and compound semiconductors respectively, and an account is given of the nucleation, growth and structure, both crystallographic and electrical, of autoepitaxial films of these materials. Some discussion of preparative techniques is first provided to illustrate the basic principles of thin film growth, but experimental details are not included. The use of modern methods of surface physics to assess the influence of the substrate surface on nucleation and subsequent growth behaviour is discussed, particularly with reference to results obtained using low energy electron diffraction. Auger electron spectroscopy and molecular beam techniques. Finally, the way in which studies of autoepitaxial growth have been extended to include growth on other substrates is considered.
TL;DR: In this article, a number of calculations based on dynamical models of the nucleus are discussed and examples of the resulting densities are given for selected nuclei and for certain groups of isotopes and isotones, and comparisons are made between phenomenological and theoretically derived densities.
Abstract: Different methods of obtaining information about nuclear charge distributions are reviewed and the nature of this information is discussed. The calculations involved in the analysis of electron scattering and electronic and muonic atom measurements are described with particular reference to the approximations made and the small corrections which must be taken into account. A number of calculations based on dynamical models of the nucleus are discussed and examples are given of the resulting densities. Results are given for selected nuclei and for certain groups of isotopes and isotones, and comparisons are made between phenomenological and theoretically derived densities.
TL;DR: In this paper, a review of the nuclear scattering of strongly interacting elementary particles including nucleons, pions and anti-protons and of composite particles, and the interpretation of this scattering in terms of the optical model, is reviewed.
Abstract: The study of the nuclear scattering of strongly interacting elementary particles including nucleons, pions and anti-protons and of composite particles, and the interpretation of this scattering in terms of the optical model, is reviewed. The complications surrounding the interpretation of nuclear size information from scattering data are discussed and an indication is given of the areas of confidence and uncertainty in the determination of size parameters. The current state of knowledge on the nuclear matter distribution and particularly the neutron distribution, as obtained from theoretical approaches, coulomb energy differences and nuclear scattering is reviewed.
TL;DR: A review of the observational data on anomalous emission by OH, H2O and H2CO molecules and anomalous absorption by H 2CO molecules is presented in this paper.
Abstract: A review of the observational data on anomalous emission by OH, H2O and H2CO molecules and on anomalous absorption by H2CO molecules. Various theories advanced to account for these data and some models of a few particular sources are discussed.
TL;DR: In this article, the authors describe early techniques as well as the recent methods using saturated absorption that promise an accuracy of 1:1012 or better and which thereby may rival the precision of microwave frequency standards.
Abstract: The article reviews various aspects of the problem of stabilizing the wavelengths of gas lasers. It describes early techniques as well as the recent methods using saturated absorption that promise an accuracy of 1:1012 or better and which thereby may rival the precision of microwave frequency standards.
TL;DR: In this paper, the impact of radiation on the functional properties of amorphous materials in a wide range of practical applications is reviewed systematically with a view to guiding future physical research.
Abstract: Amorphous forms of semiconductors and insulators are increasingly used in various electronic devices and in other technologically advanced materials such as laser hosts and light guides. These devices will sometimes be required to retain their performance while under heavy irradiation by high energy particles and photons. With a view to guiding future physical research, the impact of such irradiation on the functional properties of amorphous materials in a wide range of practical applications is reviewed systematically. After defining some environments, a list of about sixty classes of electronic and optical devices is broken down into sub-elements and the occurrence, role and irradiation problems of the amorphous sub-elements are discussed and analysed as well as the more general problems of producing tolerance to radiation in devices. The detailed analysis leads to a set of balanced recommendations for future physical research on the amorphous state in fields which will support the development of a radiation-tolerant device technology.
TL;DR: In this paper, an account is given of optical coherence theory as it existed in the 1950's when only thermal sources and slow detectors were available and it sufficed to characterize the coherence and polarization properties of an electromagnetic field by second-order correlation functions.
Abstract: An account is given of optical coherence theory as it existed in the 1950's when, essentially, only thermal sources and slow detectors were available and it sufficed to characterize the coherence and polarization properties of an electromagnetic field by second-order correlation functions. The necessity for a more sophisticated specification of the coherence properties of fields, involving the use of higher-order correlation functions, first hinted at by the Hanbury-Brown-Twiss experiments and emphasized by the advent of the laser, is then introduced. Both classical and quantum mechanical treatments are discussed, each leading, in almost all cases of practical interest, to similar results. It is seen that the development of fast detectors enabled the higher-order correlation functions to be measured using photon counting techniques and an account of experimental work verifying the complete theory using such techniques is given. The review concludes with a discussion of some developments in associated areas whose origin lies in the resurgence of interest in coherence theory during the last decade.
TL;DR: In this paper, the effects of delayed neutrons from fast fission on the temporal behaviour of a fast breeder this paper were discussed. And the role of the nuclear Doppler effect should the reactor undergo a power excursion under accident conditions was discussed.
Abstract: The nuclear physics aspects of fast reactor research and development are reviewed with particular emphasis on the liquid metal fast breeder reactor. The uranium-plutonium breeding cycle is discussed and the sensitivity of the cycle to the competing processes of radiative capture and fission is considered. Measurements of the capture-to-fission ratio alpha are given and methods of defining the breeding ratio of a system are examined. The prompt neutron fission yield and the prompt neutron energy spectrum are mentioned and measurements of fast neutron cross sections are reviewed. Two aspects of reactor safety are dealt with: the effect of delayed neutrons from fast fission on the temporal behaviour of a fast reactor; and the role of the nuclear Doppler effect should the reactor undergo a power excursion under accident conditions. Phenomenological nuclear modelling is discussed with reference to coupled channel optical and fluctuating compound nucleus models.