Calculated lamellar binding. I
Van der Walls bound lamellar solids interlayer binding energy computational model, discussing talc and pyrophyllite equilibrium stacking arrangements and force constants
Phillips, J. M.↗
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Adhesion of metals to a clean iron surface studied with LEED and Auger emission spectroscopy.
Discussion of the results of adhesion experiments conducted with various metals contacting a clean iron surface. The metals included gold, silver, nickel, platinum, lead, tantalum, aluminum, and cobalt. Some of the metals were examined with oxygen present on their surface as well as in the clean state. The results indicate that, with the various metals contacting iron, the cohesively weaker will adhere and transfer to the cohesively stronger. The chemical activity of the metal also influenced the adhesive forces measured. With oxygen present on the metal surface, the adhesive forces measured could be correlated with the binding energy of the metal to oxygen.
Buckley, D. H.↗
An ESCA study of lunar and terrestrial materials.
The technique of electron spectroscopy for chemical analysis (ESCA) is used to obtain rapid, nondestructive elemental analyses of selected lunar samples, and the chemical shift of the Fe(2p) line in lunar materials is found characteristic of iron in the Fe(2+) state. A difference in binding energy of approximately 0.5 eV is observed between the 0(1s) levels of the terrestrial minerals fayalite and quartz, and effects due to surface oxidation and absorption are also observed in terrestrial materials. The new ESCA technique is based on energy analysis at high resolution of electrons emitted from the surface of a sample on irradiation with X rays and is valuable for the study of the electronic structure of atoms and molecules.
Huntress, W. T., Jr.↗
Model potential calculations of lithium transitions.
Semi-empirical potentials are constructed that have eigenvalues close in magnitude to the binding energies of the valence electron in lithium. The potentials include the long range polarization force between the electron and the core. The corresponding eigenfunctions are used to calculate dynamic polarizabilities, discrete oscillator strengths, photoionization cross sections and radiative recombination coefficients. A consistent application of the theory imposes a modification on the transition operator, but its effects are small for lithium. The method presented can be regarded as a numerical generalization of the widely used Coulomb approximation.
Caves, T. C.↗
The case against Planet X.
The dynamical consequences of the hypothetical trans-Plutonian planet suggested by Brady (1972) are considered. It is concluded that the combination of large mass and unusual orbital inclination would have two serious effects on the solar system. The angle between the solar axis and the normal to the ecliptic would suffer large variations with a period of a few times ten million years, and the coplanar configuration of the outer solar system would be disrupted on a time scale of 1 m.y. The large residuals in the orbit of Halley's comet which prompted the suggestion of a trans-Plutonian planet can be explained in terms of nongravitation forces and the weak orbital binding energy of this object.
Goldreich, P.↗
Hydrogen atom in intense magnetic field.
The structure of a hydrogen atom situated in an intense magnetic field is investigaged. Three approaches are employed. An elementary Bohr picture establishes a crucial magnetic field strength, H sub a approximately equal to 5 x 10 to the 9th G. Fields in excess of H sub a are intense in that they are able to modify the characteristic atomic scales of length and binding energy. A second approach solves the Schrodinger equation by a combination of variational methods and perturbation theory. It yields analytic expressions for the wave functions and energy eigenvalues. A third approach determines the energy eigenvalues by reducing the Schrodinger equation to a one-dimensional wave equation, which is then solved numerically. Energy eigenvalues are tabulated for field strengths of 2 x 10 to the 10th G and 2 x 10 to the 12th G. It is found that at 2 x 10 to the 12th G the lowest energy eigenvalue is changed from -13.6 to about -180 eV in agreement with previous variational computations.
Canuto, V.↗
Minimum mass of a neutron star.
The equation of state at subnuclear densities is considered together with the average binding energy per nucleon and the possibilities for a conversion of a neutron star into a white dwarf. It is found that the stable minimum mass with a core of pure neutron gas is equal to 0.067 units in terms of the solar mass, and with a core clustered with heavy nuclei equals 0.093 units. The real minimum mass is probably somewhere between these two numbers.
Leung, Y. C.↗
Gamma-ray bursts during neutron star formation. Gamma-ray bursts and transient X-ray sources
Discussions are presented of the associations between cosmic gamma ray bursts and transient X-ray sources, and the release of gravitational binding energy during the formation of neutron stars. The model for studying the associations is described along with the release of neutrinos during the collapse of white dwarfs.
Cohen, J. M.↗
Rotating neutron star models and pulsars
Recently developed equations of state are used to construct fully relativistic models of rotating neutron stars. All of these stable neutron star models are bound. Consideration of binding energies suggests that very-low-mass neutron stars will not be formed in supernova explosions. Some criteria for equations of state are derived from a comparison with observations. Limits for the physical parameters of the Crab pulsar are obtained. In addition, we find that cosmic-ray protons cannot be produced by pulsars.
Boerner, G.↗
Dipole and quadrupole integrals for the C I, N I, and O I sequences
The Coulomb approximation tables of Oertel and Shomo, together with binding-energy values obtained by a screening approximation, have been used to produce values of the dipole and quadrupole radial integrals needed in obtaining transition probabilities for ions of six, seven, and eight electrons. Some comparisons with more rigorously calculated values show that the present values are quite accurate, especially for ions of higher atomic number.
Kastner, S. O.↗
Hadron star models
The properties of fully relativistic rotating hadron star models are discussed using models based on recently developed equations of state. All of these stable neutron star models are bound with binding energies as high as about 25%. During hadron star formation, much of this energy will be released. The consequences, resulting from the release of this energy, are examined.
Cohen, J. M.↗
Wear and interfacial transport of material
Bonding across the interface for two solids in contact and the subsequent transfer of material from one surface to another is a direct result of the interfacial bonds being stronger than the cohesive bonds in either of the two solids. Surface tools such as LEED, Auger emission spectroscopy, field ion microscopy, and the atom probe are used to examine adhesive contacts and to determine the direction, nature, quantity of material transfer and properties of the solids which effect transfer and wear. The electronic nature, cohesive binding energies, surface structure, lattice disregistry and distribution of species in surface layers are all found to effect adhesion and transfer or transport for clean surfaces in solid state contact. The influence of adsorbed and reacted surface films from fractions of a monolayer to multilayer reactive films are considered. It is shown that even fractions of a monolayer of surface active species such as oxygen and sulfur can markedly inhibit adhesion and transport.
Buckley, D. H.↗
The stability of supermassive stars in the Parametrized Post-Newtonian framework
The binding energy and stability of supermassive stars (SMS's) are examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordvedt. The PPN formalism encompasses the post-Newtonian limit of virtually every theory of gravity, differentiating between theories by means of nine PPN parameters. A general expression is derived for the energy integral in the PPN framework, and those theories in which the energy will be conserved are defined. In all such theories, a SMS of radius less than a critical radius will be unstable against adiabatic radial perturbations. Present experimental limits on the PPN parameters gamma and beta do not exclude the possibility of the existence of stable, non-rotating, hydrogen-burning SMS's of masses an order of magnitude larger than the upper limit for the mass of such stars predicted in general relativity.
Duncan, M.↗
On the sputtering of binary compounds
A simple physical model is presented to describe some aspects of the sputtering of compound targets. In particular, expressions are developed for the partial sputtering yields for binary systems in terms of the elemental sputtering rates, the stoichiometric concentrations and surface binding energy. The partial yields depend non-linearly on the bulk target concentrations. Comparison of the theoretical predictions with the data on sputtering of PtSi, NiSi and Cu3Au indicates that the general features are well described.
Haff, P. K.↗
Verification of the principle of equivalence for massive bodies
Analysis of 1389 measurements, accumulated between 1970 and 1974, of echo delays of laser signals transmitted from earth and reflected from cube corners on the moon shows gravitational binding energy to contribute equally to earth's inertial and passive gravitational masses to within the estimated uncertainty of 1.5%. The corresponding restriction on the Eddington-Robertson parameters is 4(beta) - gamma 3 = -0.001 plus or minus 0.015. Combination with other results, as if independent, yields values for beta and gamma in accord with general relativity.
Shapiro, I. I.↗
Magnetic monopoles and cosmology
The number density of magnetic monopoles is calculated in the framework of big-bang cosmology on the basis of a solution to the Boltzmann transport equation in evolutionary cosmological models. The product of the mass and the transition probability of the annihilation process for magnetic monopoles is obtained relative to those for protons and is shown to be greater than about 10 to the 20th power. Based on this result, two likely conclusions are made: (1) monopoles exist, but possess a pole-antipole bound state with binding energy of the order of the monopole rest mass; or (2) magnetic monopoles do not exist.
Adams, P. J.↗
On the sputtering of binary compounds
A simple physical model is presented to describe some aspects of the sputtering of compound targets. In particular, expressions are developed for the partial sputtering yields for binary systems in terms of the elemental sputtering rates, the stoichiometric concentrations, and surface binding energy. The partial yields depend nonlinearly on the bulk target concentrations. Comparison of the theoretical predictions with the data on sputtering of PtSi, NiSi, and Cu3Au indicates that the general features are well described.
Haff, P. K.↗
On the fragmentation of cosmic gas clouds. I - The formation of galaxies and the first generation of stars
The formation of galaxies is studied in the context of the fragmentation of massive diffuse ionized gas clouds. A semiquantitative discussion of the role of cooling indicates that there is a characteristic mass of a galaxy (of the order of 500 billion solar masses) which can fragment out of an ionized medium of density not exceeding 10 to the -25th power g/cu cm, whereas more massive galaxies attain a characteristic radius of the order of 60 kpc. The relationship between binding energy and mass is investigated for spheroidal galaxies. The role of H2 and Ly-alpha cooling in the fragmentation of primordial gas clouds is evaluated, and relatively qualitative arguments indicate that the first stars have masses of at least 0.3 solar mass with a characteristic mass of approximately 20 solar masses. When the average heavy-element abundance by mass exceeds about 0.00001, heavy-element cooling prevails over Ly-alpha cooling, and subsequent fragmentation forms second-generation stars of low characteristic mass.
Silk, J.↗