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Experimental Evidence For The Mechanism Of Charge Transfer Into Continuum States, G. B. Crooks, M. Eugene Rudd

M. Eugene Rudd Publications

We have observed a prominent peak in the energy spectrum of electrons ejected in the forward direction from helium bombarded by protons ranging in energy from 100 to 300 keV. The peak occurs at an ejected-electron velocity equal to the velocity of the incident proton. The experimental results verify the existence of the mechanism of charge transfer into continuum states of the incident ion.

Emission Of Auger Electrons Resulting From Symmetric Argon And Neon Ion-Atom Collisions, R. K. Cacak, Q. C. Kessel, M. Eugene Rudd

M. Eugene Rudd Publications

Cross sections for the emission of Auger electrons from excited atoms and ions produced in symmetric Ar⁺-Ar and Ne⁺-Ne collisions have been measured at ion energies from 50 to 300 keV. A simple model is proposed to explain the dependence of the cross section on the impact energy; the predicted results agree well with the experiment. Also, the argon x-ray data of Saris and Onderdelinden are compared with the model and with the results of this experiment.

Auger Electrons From Argon With Energies 150-210 Ev Produced By H+ And H2 Impacts, D. J. Volz, M. Eugene Rudd

M. Eugene Rudd Publications

Secondary electrons in the energy range 150-210 eV produced by 125-300-keV H⁺ and H₂⁺ impacts on argon gas are measured as a function of their energy and angle of emission. Discrete line spectra are due to Auger transitions from L₂ and L₃ vacancy states as well as satellite transitions from multivacancy states. The widths, energies, and branching ratios of the L₂ and L₃ vacancy states are presented. Widths of these states are appreciably greater than those obtained with electron impact excitation. This can be attributed to the recoil velocities of the target atom …

(15) The Papers Of Robert H. Goddard, Volume Iii: 1938-1945 [Appendices], Robert H. Goddard, Esther C. Goddard, G. Edward Pendray

The Papers of Robert H. Goddard

Meticulously curated and edited by Esther C. Goddard and G. Edward Pendray, The Papers of Robert H. Goddard is a 1700-page 3 volume set published in 1970. The set presents a careful and exhaustive chronological presentation of Robert Goddard’s life through diary snippets, correspondence, publications, speeches, patent outlines, school papers, press, reports and more.

These are the Appendices across all three volumes of The Papers of Robert H. Goddard. They are split into six parts:

1. Affidavits Concerning Rocket and Other Ideas, 1924-1942
2. Description of Affidavits Selected as Important by Robert H. Goddard, 1933-1934
3. Published Articles and Papers …

(12) The Papers Of Robert H. Goddard, Volume Iii: 1938-1945 [1938: Pressure-Tank Rockets Concluded], Robert H. Goddard, Esther C. Goddard, G. Edward Pendray

The Papers of Robert H. Goddard

Meticulously curated and edited by Esther C. Goddard and G. Edward Pendray, The Papers of Robert H. Goddard is a 1700-page 3 volume set published in 1970. The set presents a careful and exhaustive chronological presentation of Robert Goddard’s life through diary snippets, correspondence, publications, speeches, patent outlines, school papers, press, reports and more.

This section covers the year 1938, concluding Goddard's work with pressure-tank rockets. Following this, he would focus his attention on developing turbine-driven pumps for liquid propellants.

This section contains correspondence by, to, and about Robert H. Goddard from the following people and entities: William R. Enyart, …

A Quasi-Lattice Model Of Simple Liquids, Jesse Herbert Collins

Doctoral Dissertations

"A cellular model of simple liquids is proposed which eliminates the objectionable feature of long range order found in other cell models. The volume is divided into N identical spherically symmetric cells, each occupied by one molecule. The cell-center density distribution relative to an average given cell center forms a series of Gaussian peaks whose width is proportional to the square root of the distance from the given cell center. The number of cell centers and average radial distance represented by each of the peaks correspond to a face-centered cubic lattice. The molecular pair distribution function is determined for several …

Radiative Lifetime Of The A¹Π State And The Transition Moment Variation Of The Fourth Positive Band System Of Carbon Monoxide, Joseph George Chervenak

Doctoral Dissertations

"The lifetime of the A¹π state of carbon monoxide has been measured using a pulsed invertron excitation source and delayed coincidence measurement technique on the fourth positive system. Eighteen bands, originating from the upper states v' = 0 to 5, were examined at pressures between 500 and 50 microns, with no pressure dependence noted. The data were corrected for photon "pile up" and least-squares fitted to the sum of two exponentials. The transition moment was found to vary and was expanded about the r-centroid of the v' = 0 to v" = 0 transition. Oscillator strengths are calculated and compared …

An Experimental And Theoretical Study Of The Nucleation Of Water Vapor On Ions In Helium And Argon, Daniel R. White

Doctoral Dissertations

"The nucleation of water vapor on ions in atmospheres of helium and argon was studied using an expansion type cloud chamber. Separation of the positive and negative ions was achieved so that the nucleation could be studied as a function of both the sign of the ionic charge and the supersaturation. A semiphenominological theory was developed as an extension of the classical theory to include the effects of the ionic charge on the nucleation process. The theoretical model of the prenucleation embryo was assumed to possess an oriented dipole surface layer with the direction of orientation dependent on the sign …

A Study Of Far Infrared Grid Filters, Harold Victor Romero

Doctoral Dissertations

"The diffraction theory for the transmission of electromagnetic fields through a grid in a dielectric is derived and experimentally checked in the visible wavelength region. In the far infrared, an approximate mathematical representation is found to describe the grids in dielectrics. The empirical equations in the far infrared are combined with the electrical circuit-transmission line analog for inductive grids. Detailed structure of the transmittance versus wave number curves are presented. Then the theory of multielement grid filters is derived and compared with experiment. The properties of the filters can be predicted from a knowledge of the characteristics of the individual …

Absolute Excitation Cross Sections Of He⁺ In 20-100 Kev He⁺-He Collisions Using Energy-Loss Spectrometry, Donald Roy Schoonover

Doctoral Dissertations

"Application of positive-ion energy-loss spectrometry has been extended to include experimental determination of absolute excitation cross sections of ground state helium ions. Helium ion-atom collisions were studied for impact energies ranging between 20-100 keV, in 10 keV intervals. The data were taken with an apparatus resolution between 0.6-o.8 eV FWHM. Cross sections for transitions from ground state to the second and third principal quantum levels of the ion plotted as a function of impact energy were still rapidly increasing at 100 keV. The cross sections at this energy were 1.64(± 0.28) x 10⁻¹⁸cm² for He⁺(l²s_1/2) -> He⁺(n = …

Investigation Into The Monotonic Magnetostriction And Magnetic Breakdown In Cadmium, James Milo Carter

Doctoral Dissertations

"Observations of the monotonic magnetostriction of cadmium at 4.2 K and in fields of 65 kilogauss have been made. The angular dependence of an extremal point (H_m) in the monotonic magnetostriction is found to follow inverse cosine behavior. The magnitude of H_m (27 kG) for fields parallel to [0001] is in fair agreement with the onset of γ_1/3 from the breakdown of the trifoliate orbit, γ. The range of observation of h_m coincides with the reported range of the trifoliate orbit. A "klink" in the monotonic magnetostriction is demonstrated. The "klink" field, H_k, …

Realistic Impulsive P Wave Source In An Infinite Elastic Medium, Joseph Hugo Hemmann

Doctoral Dissertations

"The generally assumed instantaneous impulsive pressure sources for an elastic P wave in an infinite medium lead to basic contradictions, a step function source yielding infinite displacements as the shear modulus goes to zero, and the total energy radiated by a delta function (or any derivative of the delta function) source being infinite. By noting that the character of the solution in the elastic region must match the acoustic case near the source, a realistic impulsive pressure source is postulated which has a finite time history. The elastic field produced by this source is then obtained in closed form. A …

Structures And Relationships Of Some Perovskite-Type Compounds, Christian Michel

Doctoral Dissertations

"A model for crystallographic transitions in perovskites is proposed. The model consists of regular octahedra sharing corners and topologically able to rotate without distortion around their three-fold axes. This model, with R3̄c symmetry (18e position) can be described in terms of a continuous rotation of angle, w, of octahedra from two ideal symmetry forms: the hexagonal close-packed and the cubic face-centered configurations. A parametric relation is derived between w and the rhombohedral cell angle, α, or the corresponding hexagonal axial ratio c/a . A wide range of atomic structures based on a framework of regular or slightly distorted octahedra sharing …

The Surface Effects Of Alkali Halides In The Infrared, Vincent Joseph Llamas

Doctoral Dissertations

"The surface state extension of the shallow donor theory is reviewed. The surface state theory and its applications to F-centers of alkali halides is presented. Experimental infrared data show an absorption which seems to correspond with the ground state to first excited state transition. Surface state concentrations of F-centers as a function of depth into the crystal are given. The ratio of surface to bulk cross sections in KBr and experimental calculations of effective masses in various alkali halides are in excellent agreement with theory. The theoretical cross sections are derived from transition probabilities. However, lack of excited states, the …

Theory Of Shallow Donor Impurity Surface States, Vidal Emmanuel Godwin

Doctoral Dissertations

"A variational approach has been used to solve the effective-mass equation, when the impurity ion is located at a depth d from the surface of a semiconductor, where 0 < d < d_b and d_b represents the case when the impurity ion is in the bulk of the semiconductor. The ground state and the excited state having the largest electric dipole coupling to the ground state have been determined. We have plotted the energy dependence on the depth of the impurity ion from the surface of the semiconductor. The energy has also been calculated as a function of the orientation of the …

Application Of The Weiss Molecular Field Theory To The Lattice Of The B-Site Spinel, Wayne Edmund Holland

Masters Theses

"The Weiss molecular field theory has been applied to the lattice of the B-site spinel. The forms of the ordering temperatures and the asymptotic Curie temperature have been determined for a sixteen-sublattice model with collinear spins. The theory has been applied to the problem of determining the exchange integrals for systems of the form Aa₁₋ₓAbₓCr₂X₄ and ACr₂Xa_4(1-y)Xb_4y. The theoretical results have been compared to the experimental data for the systems Hg₁₋ₓCdₓCr₂S₄, Zn₁₋ₓCdₓCr₂Se₄, and CdCr₂S_4(1-y)Se_4y in an attempt to determine the exchange integrals"--Abstract, page ii.

Cross Section For Excitation Of The Fourth Positive Band System In Carbon Monoxide By 20-120 Kev Protons, John T. Park, D. R. Schoonover, George W. York

Physics Faculty Research & Creative Works

Excitation cross sections for the fourth positive band system in carbon monoxide have been determined from studies of the energy-loss spectra of 20-120-keV protons incident on gaseous CO targets. The energy-loss spectra had an energy resolution of about 2 eV. Prominent peaks in the spectra were observed at 8.5 and 13.8 eV. The first peak is believed to be due to excitation of the fourth positive band system of CO (X+1A 1, while the 13.8-eV peak covers a number of possible states, including the B+2 and the C+1 states. Changes in the slope of the ionization continuum were noted at …

Excitation Of Hydrogen Atoms By Fast Protons, Edward Ellis Fitchard

Physics Theses & Dissertations

In this thesis a theoretical study is made of excitation of hydrogenic atom by charged particles such as protons or electrons. The approximation to the cross section for an inelastic scattering process is obtained under the following radically simplifying assumptions. The projectile is represented in its initial and final state by plane waves. All distortions are neglected whether they originate in an inelastic process or an elastic deflections of the charged particle by the nucleus. The perturbation of the atomic orbits between which the projectile induces transitions is neglected. Nonrelativistic hydrogenic wave functions are used for the electronic states. In …

The Design And Construction Of A Constant Acceleration Drive System For Mössbauer Experiments, James Donald Russell

University of the Pacific Theses and Dissertations

An excited nucleus may undergo a transition to its ground state by the emission of a gamma ray. The nucleus, if free to do so, will recoil and take some of the transition energy as recoil energy leaving less energy for the emitted gamma ray. This gamma ray does not have enough energy to excite a similar nucleus and will, therefore, not by resonantly absorbed due to the fact that the natural linewidth of the gamma ray is so much smaller than the energy taken by the emitting atom and the similar energy needed by the absorbing atom.

In 1958 …

Geophysical Institute Annual Report 1969-70, Geophysical Institute

GI Reports

The 1969-70 Geophysical Institute Annual Report presents an overview of the year’s scientific research achievements across the Institute’s disciplines, alongside operational summaries covering finances, administrative changes, and other key activities.

Some New Approaches To Shallow Impurity States, Wayne E. Tefft, Robert John Bell, Harold V. Romero

Physics Faculty Research & Creative Works

A variational calculation of shallow surface impurity states including image-charge and anisotropic mass effects was performed using two different sets of orthogonal functions. The first set was obtained by varying the Bohr radius in the hydrogenic functions, separately for each state. In the second set the Bohr radius was allowed to become anisotropic, and the elements were separately treated as variational parameters. In each case it was shown that with certain restrictions on the variational parameters the set remained complete and orthogonal. General expressions for the energy eigenvalues for both the bulk and surface problem obtained from the first set …

Infrared Reflectivity Of Doped Insb And Cds, Thomas J. Mcmahon, Robert John Bell

Physics Faculty Research & Creative Works

The coupling of free carriers and lattice-vibrational modes in CdS and InSb was investigated by using reflectance measurements. When the free-carrier concentration is such that the longitudinal-optical-mode frequency is at or near the plasma frequency, the longitudinal mode takes on a mixed character and is shifted in a manner similar to that described by Varga in 1965, while the transverse mode remains fixed. The electron effective masses in such a situation can be determined with the lattice effects excluded. In the case of CdS, the polaron mass and additional absorption in the plasma mode above the longitudinal-optical phonon frequency must …

Heavy-Particle Energy-Loss Spectrometry: Inelastic Cross Sections For Protons Incident Upon Helium, John T. Park, F. D. Schowengerdt

Physics Faculty Research & Creative Works

A method is described whereby absolute cross sections are obtained from inelastic energy-loss spectra induced by ions incident upon gaseous targets at energies of 25-125 keV. Inelastic energy-loss spectra of helium for proton impact are presented. Apparent differential cross sections and absolute total cross sections are obtained from the spectra. Total cross sections for the sum of the 1S1→2S1 and 1S1→2P1 excitations are reported, along with estimates of the relative contributions of each. Total ionization cross sections, total cross sections for inelastic scattering, apparent energy distributions of ejected electrons, and partial ionic stopping powers are also reported. The excitation cross …

A Heavy-Ion Energy Loss Spectrometer, John T. Park, F. D. Schowengerdt

Physics Faculty Research & Creative Works

A high-resolution system for the measurement of the energy loss spectra of 20-250 keV heavy ions incident on gas targets is described. The high resolution is obtained by decelerating the ion beam to a low, well-defined energy before performing the energy analysis. The energy loss spectrum is determined by changing the accelerator energy to compensate for energy lost in collisions with the gas atoms. The system is arranged so that normal fluctuations in the accelerator's power supply do not affect the energy resolution. The resolving power of the system is 2.5x104. The primary proton beam has a detected WHM of …

Charge-Transfer Cross Sections For Negative Ions On Atomic And Molecular Targets, W. (William) R. Snow, R. D. Rundel, R. Geballe

Physics Faculty Research & Creative Works

Charge-transfer cross sections for H^- on O, O₂, and NO₂; O^- on H, O, H₂, O₂, and NO₂; and C^- on H and O have been measured over an energy range of 0.5 to 4 keV using a modulated crossed-beam apparatus. The experimental cross sections are compared with theories of resonant and non-resonant charge transfer based on a two-state approximation. For the reactions H^-+O O^-+H, the cross sections are found to be consistent with detailed balancing. The effect of electron detachment on charge-transfer …

Entropy Of The Mixed State Of Some Low-Κ Type-Ii Superconductors, Don Carlos Hopkins, R. R. Rice, J. M. Carter, J. D. Hayes

Physics Faculty Research & Creative Works

The entropy of the mixed state of type-II superconductors with low κ(∼1) is studied for the alloys Pb_0.96Tl_0.04 and In_0.88Sn_0.12. The current theories are reviewed for approximations valid near Hc1 and near Hc2. The experiments show for the most reversible sample (Pb_0.96Tl_0.04) that (SB)_T of the mixed state depends only on temperature, and that (ST)_B increases linearly with B from its value for the superconducting state until it drops discontinuously to its normal state value at H_c2. There is no abrupt increase in the specific …

A Study Of Some Matrix Elements For The Four-Pion Decay Mode Of Neutral Bosons, George Victor Weller

Masters Theses

No abstract provided.

Formation Of Carbides On Tungsten Wires, W. J. Croft, Kaare J. Nygaard

Physics Faculty Research & Creative Works

It has been found that layers of tungsten carbide form on tungsten wires processed under ultra-high vacuum. The carbide is formed from carbon impurities in the volume of material.

Vibrational Excitation By Electron Impact Near Threshold In H2, D2, N2, And Co, Paul Burrow, G.J. Schulz

Paul Burrow Publications

The trapped-electron method is applied to the measurement of the slopes of the vibrational cross sections near their respective thresholds. Absolute values are obtained by normalization to positive-ion cross sections. The values obtained in H₂ are 43 for v=1, 0.72, for v=2, 0.04, for v=3, and 0.003, for v=4, in units of 10^-18 cm²/eV. The values for N₂ are 2.5 for v=1 and about 0.02 for v=2, whereas, the values for CO are much larger, i.e., 120 for v=1 and 2.4 for v=2. Various corrections that are …

Hyperfine Interaction In Gd In Diamagnetic, Metallic Hosts, Richard B. Frankel

Physics

Mössbauer effect data for dilute, paramagnetic Gd in the diamagnetic, metallic hosts YAl₂, YbAl₂ and Al are analyzed and yield a local conduction electron polarization contribution to the Gd hyperfine field of +140 kOe.