Physical Sciences and Mathematics Commons^™

Construction Of A Lithium Vapor Oven For Electron Capture And Multiple Ionization Experiments, Oliver Woitke

Masters Theses

A Li vapor oven, to be used as a source of Li target atoms in electron capture and multiple ionization experiments, was designed and installed in the beamline of the Van de Graaff accelerator at Western Michigan University. The oven was tested using two different projectile beams, protons and He+. The test results indicate that Li evaporated from the oven in the form of a cloud rather than as a jet spray. For He+ colliding with Li it was found that the projectile single-electron loss yield is about three orders of magnitude larger than the single-electron capture yield, as expected …

A Study Of The Transfer Matrix Method For The Classical Statistical Mechanics Of One Dimensional Systems, Dietmar R.A. Johlen

Masters Theses

Two formalisms using the transfer matrix technique, the first one by Gupta and Sutherland (1976) and the second one by Guyer and Miller (1979), are investigated and a proof is given for their equivalence.

Furthermore, it is pointed out that previous studies neglected the difficulties that arise from nonhermitian pseudo Hamiltonian. This work proves that the same results are obtained by taking into account the nonhermiticity of the pseudo Hamiltonian.

Thus, the transfer integral technique is extended to nonhermitian pseudo Hamiltonians.

Charge Conservation In The Incommensurate-Commensurate Transition Of Charge Density Waves, Jörg Kastrup

Masters Theses

W ith the complex continuation method, introduced by Gupta and Sutherland (1976), the grand partition function for the sine-Gordon model of charge density waves may be calculated without violation of charge conservation. Contrary to previous works by Okwamoto, Takayama and Shiba (1979) and Turkevich and Doniach (1982) the chemical potential becomes temperature dependent. By direct comparison of numerical results with those of the above mentioned authors it is shown that the incommensurate-commensurate transition does not occur in the previously predicted temperature range.

Localization Of Light In One Dimensional Randomly Disordered Dielectric Medium, K. Balaji

Masters Theses

The concept of localization of electrons in semiconductors has been known ever since the 1960's when P. W. Anderson and N. F. Mott made detail investigations on the transport properties of alloys. At the end of the last decade, however, physicist started looking for localization in other systems. Specifically, they looked at the localization of light and acoustic waves in disordered systems. Localization is a property which arises for all wavelike excitations in disordered media.

In this study we analyze the localization of light in one dimensional randomly disordered dielectric medium using computer simulation (numerical integration method) technique. The results …

Prediction Of Paper Color: A Process Simulation Approach, Mayank Chaturvedi

Masters Theses

A simulation model was developed for a dye mixing process and for the prediction of the optical properties of the paper. The model was integrated with the MAPPS (Modular Analysis of Pulp and Paper Systems) simulation software package. The model was validated using dyed handsheets made in a laboratory and dyed paper made on a pilot papermachine. Validation comprised of prediction of the optical properties of the handsheets and the machine-made paper which contained various combinations of three non-fluorescent dyes. Sheet reflectances were predicted at 20 nanometer intervals for discrete light wavelength range of 400 to 700 nanometers and verified …

Double Differential Cross Sections For State-Selective Electron Capture By Low-Energy Ar4+ And Ar5+ Ions From He And Ar, Serefettin Yaltkaya

Masters Theses

Doubly differential cross sections, in angle and energy, for state-selective single-electron capture from He and Ar by Ar⁴⁺ and Ar⁵⁺ ions have been studied experimentally at laboratory impact energies of 25q, 50q, and lOOq eV (q = 4 and 5, where q is the ion charge state) and at laboratory scattering angles between 0° and 5.5°, by means of translational energy spectroscopy. The translational energy-gain spectra show that only a few final states are selectively populated. Final-state transition probabilities were found to depend strongly on the charge state of the projectile ion and the ionization potential of the …

Single And Double Ionization Of Helium By Highly Charged Sulfur Ions, Karen M. Lifrieri

Masters Theses

Single and double ionization of helium by highly charged sulfur projectiles is investigated over an energy range of 0.16 to 1.6 MeV/u. Absolute cross sections for the processes of pure ionization, ionization associated with single capture, and ionization associated with single loss by S^6,13+ projectiles were experimentally determined and compared with previous results and theories. Ratios of double-tosingle ionization for each outgoing projectile charge state were also determined and compared with theory. The pure ionization ratios for S⁶⁺ at the highest energies investigated show the q²/E dependence predicted by Knudsen et al. (1984). For S^{13+ …}