Physics Commons^™

A Theoretical Study Of Synchronous Proton Transfer In (Hf)N, (H2O) N, And (Hcl) N Where N = 3, 4, 5, Johnny Yang

Honors Theses

For (HF)_n, (H₂O)_n, and (HCl)_n (n = 3 − 5), we have rigorously characterized the structures for the minima and transition states for synchronous proton transfer (SPT) with the CCSD(T) method and aug-cc-pVTZ basis set. The electronic barrier heights (∆E^†) associated with these transition states have also been computed with the explicitly correlated CCSD(T)-F12 method and the aug-cc-pVQZ-F12 basis set (abbreviated aQZ-F12). (HCl)_n (n = 3 − 5) SPT transition states have not been previously identified to the best of our knowledge, and they have been found …

Determination Of The Rydberg Constant From The Emission Spectra Of H And He+, Kyle D. Shaffer

Ramifications

Abstract

In this experiment, the Rydberg constants for the hydrogen atom and He⁺ were determined by analysis of the emission spectra of Hand He, respectively, in comparison to the principal quantum numbers of each transition. Using both a hydrogen and then a helium atomic lamp attached to a 0.5 m grating spectrometer and a photomultiplier detector (PMT), a change in voltage detected by the PMT can be paired with a corresponding wavelength passing through the spectrometer from each emission peak in the visible to ultraviolet range. The peaks acquired from this change in voltage were analyzed to find their …

On Laser-Induced Plasma Containing Hydrogen, Ghaneshwar Gautam

Doctoral Dissertations

Laser-induced micro-plasma dynamics are investigated in laboratory air, ultra-high-pure hydrogen gas, and hydrogen-nitrogen gas mixtures. The dissertation focuses on atomic spectroscopy of hydrogen in the visible region.

Line-of-sight measurements are analyzed to obtain spatial distributions of electron densities and excitation temperatures. The studies include evaluation of self-absorption phenomena. The plasma dynamics occur initially well above re-entry speeds and diminish to hypersonic and then supersonic expansions. Expansion velocities are measured that are above three hundred times the speed of sound in standard atmosphere. Optical breakdown is induced by using pulsed laser radiation. Emission spectra are collected by employing a spectrometer equipped …

Continuity Of Heavy Rydberg Behaviour In The Ungerade Ion-Pair States Of H2, Alexander M. Chartrand, Robert J. Donovan, Kenneth P. Lawley, Elizabeth Mccormack

Physics Faculty Research and Scholarship

Heavy Rydberg behaviour and absolute quantum defects are reported for resonances in the ungerade manifold of H₂ above the (1s, 3l) dissociation limit. The continuity of the vibrational progression of the B''B-bar state through the crossing with the 3p asymptote is demonstrated and a predominantly diabatic picture of the vibrational motion emerges, indicating that the ion-pair resonances possess little 6¹Σ_u⁺ state character.

Dissociative Excitation Of H2 In An Rf Plasma, John Carlson

Macalester Journal of Physics and Astronomy

Plasma-enhanced chemical vapor deposition is a widely used method for depositing thin films. In order to optimize the properties of the films, it is important to understand the plasma processes that occur during film growth. In this research we use optical emission spectroscopy in order to measure the spectral emission lines of a plasma produced with hydrogen gas. In conjunction with other measurements and modeling, these measurements can provide insight to the electron energy distribution of the plasma.

Observations Of The High Vibrational Levels Of The B′′B̄ 1Σu+ State Of H2, Alexander M. Chartrand, W. Duan, R. C. Ekey, Elizabeth Mccormack

Physics Faculty Research and Scholarship

Double-resonance laser spectroscopy via the E F ¹Σ_g⁺, v'=6, J'=0-2 state was used to probe the high vibrational levels of the B"B-bar ¹Σ_u⁺ state of molecular hydrogen. Resonantly-enhanced multiphoton ionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v=51-66 levels for the B"B-bar state of H₂ are reported, which, taken with previous results, span the v=46-69 vibrational levels. Results for energy levels are compared to theoretical close-coupled calculations [L. Wolniewicz, T. …

Inelastic Scattering Matrix Elements For The Collision B (2P1/2) + H2(J) → B (2P3/2) + H2(J'), Thomas A. Niday

Theses and Dissertations

Initial efforts to characterize the scattering dynamics of B + H₂ focus on computing scattering matrix elements for the fine structure transition B (²P_1/2) --> B (²P_3/2) in collisions with H₂, allowing for rotational excitation. Using a new application of the time dependent Channel Packet Method (CPM), reactant and product wave packets are prepared in the asymptotic limit on the B (²P_1/2) and B (²P_3/2) surfaces. They are propagated using the split operator method together wit a unitary transformation between the …

Tabletop X-Ray Lasers, D. C. Eder, P. Amendt, L. B. Dasilva, R. A. London, B. J. Macgowan, D. L. Matthews, B. M. Penetrante, M. D. Rosen, S. C. Silks, Thomas D. Donnelly, R. W. Falcone, G. L. Strobel

All HMC Faculty Publications and Research

Details of schemes for two tabletop size x‐ray lasers that require a high‐intensity short‐pulse driving laser are discussed. The first is based on rapid recombination following optical‐field ionization. Analytical and numerical calculations of the output properties are presented. Propagation in the confocal geometry is discussed and a solution for x‐ray lasing in Li‐like N at 247 Å is described. Since the calculated gain coefficient depends strongly on the electron temperature, the methods of calculating electron heating following field ionization are discussed. Recent experiments aimed at demonstrating lasing in H‐like Li at 135 Å are discussed along with modeling results. The …

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 …

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 …