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|Title:||Quantum mechanical molecular scattering theory: Orbiting to room temperature|
|Author(s):||Sisak, Michael Steven|
|Doctoral Committee Chair(s):||Secrest, Donald H.|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||A series of time-independent scattering calculations were done on the helium and silicon-monoxide (B =.0901 meV) system in its ground electronic state using the rigid rotor approximation. Close Coupling results were compared with those of the L-average form of Coupled States (CS), its first order perturbational improvement, the Recoupled (RE) method, and an extension of the Exponential Distorted Wave (EDW) method called the EX method. EX used the CS solution as its zeroth order member. Four energies were studied extensively. The lowest energy, 2.25 meV (equal to.4 times the potential well-depth), produced intense orbiting behavior. At this energy, CS performed very poorly, RE performed exceedingly poorly, and EX, though improving the RE results, did not significantly improve the CS results. At an energy 4 times this, CS performed a little better and the other methods were of little added value. Two higher energies (18 meV and 27 meV) were studied. CS was excellent and RE made minor improvements. EX results were significantly worse than CS. Orbiting is shown to be the factor causing the poor results at low energy. Also, great sensitivity of cross sections to slight changes in energy in the low energy range is shown.
Numerous (approx. 500) m-dependent differential cross sections are plotted. Many degeneracy averaged differential and integral cross sections are given. A 35 page table of m-dependent integral cross sections is included, as are pertinent computer programs.
|Rights Information:||Copyright 1990 Sisak, Michael Steven|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI9114416|