Physics Commons^™

Partial Radiative Recombination Cross Sections For Excited States Of Hydrogen, Patricia M. Fazio

Physics Theses & Dissertations

In calculating the radiative recombination cross sections for interstellar H II regions usually only the electric dipole term in the expansion of the interaction Hamiltonian is kept. However, conditions present in these regions permit recombination into highly excited states and the "effective size" of the atom is not much less than the wavelength of the emitted photon. These physical conditions do not meet the requirements for making the dipole approximation. A higher order approximation is to keep an additional term in the expansion of the Hamiltonian, and, therefore, to include contributions of quadrupole transitions in the calculation of the partial …

A Theoretical Model For Calculation Of Molecular Stopping Power, Yuan-Jian Xu

Physics Theses & Dissertations

A modified local plasma model based on the work of Linhard-Winther, Bethe, Brown, and Walske is established. The Gordon-Kim's molecular charged density model is employed to obtain a formula to evaluate the stopping power of many useful molecular systems. The stopping power of H₂ and He gas was calculated for incident proton energy ranging from 100 KeV to 2.5 MeV. The stopping power of O₂, N₂ and water vapor was also calculated for incident proton energy ranging from 40 keV to 2.5 MeV. Good agreement with experimental data was obtained.

A discussion of molecular effects leading …

A Theory Of Associative Detachment, Susan Elizabeth. Haywood

Dissertations, Theses, and Masters Projects

In this thesis a theory of associative detachment (A('-) + B (--->) AB + e) is presented. The theory is based on the close-coupling theory of Wang and Delos, but is more general in that final states of the nuclei (AB) are treated quantum mechanically. This is necessary since the molecule may be in any one of several vibrational states. The Schroedinger equation is reduced to an infinite set of coupled equations using carefully chosen assumptions. The coupled equations are uncoupled and the resulting equation for the wave function of the negative ion is solved to zero and first …

Electron Detachment In Negative Ion-Molecule Collisions, Mohammed Saiful Huq

Dissertations, Theses, and Masters Projects

Absolute total cross sections for electron detachment, reactive scattering, charge transfer and dissociative charge transfer have been measured for collisions of hydrogen and halogen negative ions with various molecular targets. The reactants investigated involve H('-), D('-), F('-), Cl('-), Br('-) and I('-) ions as projectiles and H(,2), D(,2), HD, N(,2), CO, O(,2), CO(,2), CH(,4) and Cl(,2) molecules as targets. The energy range of these experiments extended from about 1 eV to about 300 eV in the lab.;The threshold behavior of the detachment cross sections for the reactants H('-)(D('-)) + H(,2),D(,2) and HD has been determined. The thresholds for detachment for both …

Systematic Estimate Of Binding Energies Of Weakly Bound Diatomic Molecules, Linda L. Vahala, Mark D. Havey

Electrical & Computer Engineering Faculty Publications

There is often insufficient spectroscopic data for a full RKR inversion to yield a potential for weakly bound diatomic molecules. In these cases, parametrized functions such as the Morse or Thakkar potentials may be used to obtain estimates of the binding energy. The Thakkar potential is more flexible, and has been used successfully on some weakly bound systems. In the more usual case, the Thakkar parameter p, which determines long range behavior R^-p, is chosen by p=-a₁-1, where a₁ is the first Dunham coefficient; p is usually noninteger. The authors present …