Studies of low-energy ionic collisions Final report, 1 Oct. 1965 - 30 Sep. 1967
Ionic-molecular collisions, and collision induced dissociation of ions
Bailey, T. L.↗
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Collision excitation of positive ions in p super q configurations - Transitions between levels of the P term. II.
Electron collision excitation of positive ions, calculating collision cross sections for transitions between levels of P term
Blaha, M.↗
Inelastic molecular collisions
Collision cross sections direct measurement for determining macroscopic reaction rates in inelastic molecular collision processes in gas dynamics
Utterback, N. G.↗
Semiquantal theory of heavy-particle excitation, deexcitation, and ionization by neutral atoms. I - Slow and intermediate energy collisions
Heavy particles collision induced excitation, deexcitation and ionization rates, calculating atomic H quantum level transitions due to H and He atomic collisions at thermal energies
Flannery, M. R.↗
Three-particle collisions in a gas of hard spheres
Hard-sphere gas three-particle collision integrals, using binary collision expansion
Hoegy, W. R.↗
A preliminary study of vibrational effects in ion-dipole collisions - 'Classical tunneling'
Vibrational effects on capture cross sections and ion-molecule complexes formation based on ion- dipole collisions, noting multiple reflection probabilities and collision lifetimes
Canright, R. B., Jr.↗
Design study of general aviation collision avoidance system
The selection and design of a time/frequency collision avoidance system for use in general aviation aircraft is discussed. The modifications to airline transport collision avoidance equipment which were made to produce the simpler general aviation system are described. The threat determination capabilities and operating principles of the general aviation system are illustrated.
Bates, M. R.↗
Excitation of Mg/+/ by electron collisions.
Demonstration that the Mg II resonance doublet at 2800 A represents a suitable diagnostic tool for the study of physical conditions in the solar chromosphere. The interpretation of intensities and line profiles requires the knowledge of all electron collision cross sections, which can affect directly or indirectly the population of upper levels of the doublet. For this purpose collision cross sections for transitions between levels 3s, 4s, 5s, 6s, 3p, 4p, 5p, 3d, 4d, and 5d have been calculated in the unitarized Coulomb-Born approximation without exchange. For the 3s-3p and 3s-3d transitions the present results are in a good agreement with the close-coupling calculations of Burke and Moores (1968).
Blaha, M.↗
Collision integrals for isotopic hydrogen molecules.
The study was undertaken to determine the effects of reduced mass and differences in asymmetry on the collision integrals and thermal diffusion factors of isotopic hydrogen systems. Each system selected for study consisted of two diatoms, one in the j = 0 rotation state and the other in the j = 1 state. The molecules interacted with a Lennard-Jones type potential modified to include angular terms. A set of cross sections and collision integrals were obtained for each system.
Brown, N. J.↗
A note on mass loss during collisions between galaxies and the formation of giant systems.
Stars will be liberated from the outer portions of galaxies which interact tidally. Using models based on the density distribution observed in the E1 galaxy NGC 3379, the mass loss is computed for hyperbolic collisions on an approximate but conservative basis. Binary collisions are then summed to show that large numbers of stars will be evaporated from elliptical members of dense clusters of galaxies. An estimate of one trillion solar masses is obtained for the amount of material dispersed in the Coma cluster, and in rich very dense systems (Morgan's Type I) the large amount of tidally dispersed debris may constitute the centrally located galaxies designated cD systems which often dominate these clusters.
Gallagher, J. S., III↗
The collision singularity in a perturbed n-body problem.
Collision of all bodies in a perturbed n-body problem is analyzed by an extension of the author's results for a perturbed two-body problem (1969). A procedure is set forth to prove that the absolute value of energy in a perturbed n-body system remains bounded until the moment of collision. It is shown that the characteristics of motion in both perturbed problems are basically the same.
Sperling, H. J.↗
The relation between momentum transfer and capture and total scattering cross sections for ion-dipole collisions
Numerical values of momentum transfer cross sections sigma sub m for ion-dipole collisions are compared with the corresponding capture cross sections sigma sub c as a function of ion velocity and rotational temperature. For values of dipole moment mu from 1 to 4 Debyes the sigma sub m/sigma sub c ratio is in the range 1.2 to 2.0 (roughly). This is in contrast to the simple relation for Langevin collisions where sigma sub m/sigma sub c is equal to or approximately 1.10 independent of polarizability of the target atom. At low temperatures, the momentum transfer cross sections can be as large as 2000 A squared but they are only about 15 to 30 percent of the total scattering cross sections sigma sub S.
Dugan, J. V., Jr.↗
Asymptotic form for the cross section for the Coulomb interacting rearrangement collisions
It is shown that in a rearrangement collision leading to the formation of the highly excited hydrogenlike states the cross section in all orders of the Born approximation behaves as 1/n sq, with n the principal quantum number, thus invalidating the Brinkman-Kramers approximation for large n. Similarly, in high energy inelastic electron-hydrogenlike atom collisions the exchange cross section for sufficiently large n dominates the direct excitation cross section.
Omidvar, K.↗
Apparatus for aiding a pilot in avoiding a midair collision between aircraft
An apparatus for aiding a pilot in avoiding a midair collision between aircraft is described. A protected aircraft carries a transmitter, a transponder, a receiver, and a data processor; and an intruding cooperating aircraft carries a transponder. The transmitter of the protected aircraft continuously transmits a signal to the transponders of all intruding aircraft. The transponder of each of the intruding aircraft adds the altitude of the intruding aircraft to the signal and transmits it back to the receiver of the protected aircraft. The receiver selects only the signal from the most hazardous intruding aircraft and applies it to the data processor. From this selected signal the data processor determines the closing velocity between the protected and intruding aircraft, the range between the two aircraft, their altitude difference and the time to a possible collision.
Schrader, J. H.↗
Non-Lorentzian ion cyclotron resonance line shapes arising from velocity-dependent ion-neutral collision frequencies
An asymptotic solution of the Boltzmann equation is developed for ICR absorption, without restrictions on the ion-neutral collision frequency or mass ratio. Velocity dependence of the collision frequency causes deviations from Lorentzian line shape.
Whealton, J. H.↗
Use of the Glauber approximation in atomic collisions - A progress report.
Recent progress in the use of the Glauber (1970) theory for estimating atomic collision cross sections is reviewed. It appears that the Glauber approximation is reliable for electron-hydrogen elastic scattering and excitation at incident energies exceeding 30 eV. For more complicated atomic collisions, the usefulness of the Glauber approximation has not yet been significantly tested.
Gerjuoy, E.↗
Asymptotic form for the cross section for the Coulomb interacting rearrangement collisions.
It is shown that in a rearrangement collision leading to the formation of highly excited hydrogenlike states the cross section at high energies behaves as 1/n-squared, with n the principal quantum number, thus invalidating the Brinkman-Kramers approximation for large n. Similarly, in high-energy inelastic electron-hydrogenlike-atom collisions the exchange cross section for sufficiently large n dominates the direct excitation cross section.
Omidvar, K.↗
Electron detachment in low-energy collisions of H/-/ and D/-/ with He
The applicability of the complex-potential theory to H(-)-He collisions is investigated. Measurements are conducted of the elastic differential cross section for H(-)-He collisions, taking into account energies in the range from 5 to 120 eV. A preliminary determination is made of the energy spectrum of detached electrons. The results are interpreted in terms of the complex-potential theory. The crossing point is determined together with the general shape of the HeH(-) potential curve.
Lam, S. K.↗