In this work, experimental and theoretical approaches are applied to the study of chemical reaction
dynamics. In Chapter 2, two applications of transition state theory are presented: (1) Application of
microcanonical transition state theory to determine the rate constant of dissociation of C2F3I
after π∗ ← π excitation. It was found that this reaction has a very fast rate constant
and thus
is a promising system for testing the statistical assumption of molecular reaction dynamics. (2) A general
rate constant expression for the reaction of atoms and molecules at surfaces was derived within the statistical
framework of flexible transition state theory.
In Chapter 4, a computationally efficient TDDFT approach was found to
produce useful potential energy surface landscapes for application to non-adiabatic predissociative dynamics
of the molecule CS2 after excitation from the ground state to the singlet C-state. In Chapter 5, ultrafast
experimental results of excitation of CS2 to the predissociative neutral singlet C-state is presented. The
bandwidth of the excitation laser was carefully tuned to span a two-component scattering resonance with each
component differently evolving electronically with respect to excited state character during the quasi-bound
oscillation. Scalar time-resolved photoelectron spectra (TRPES) and vector time-resolved photoelectron
angular distribution (TRPAD) observables were recorded during the predissociation. The TRPES yield of
photoelectrons was found to oscillate with a quantum beat pattern for the photoelectrons corresponding to
ionization to the vibrationless cation ground state; this beat pattern was obscured for photoelectron energies
corresponding to ionization from the vibrationally excited CS2 cation. The TRPAD data was recorded for
two general molecular ensemble cases: with and without a pre-excitation alignment laser pulse. It was found
that in the case of ensemble alignment (Chapter 6), the “molecular frame” TRPAD (i.e. TRMFPAD) was
able to image the purely valence electronic dynamics of the evolving CS2 C-state. The unaligned ensemble
TRPAD observable suffers from excessive orientational averaging and was unable to observe the quantum
beat.
Engineering efforts were also undertaken to eliminate scattered light background signal (Chapter 7,
Appendix A) and improve laser stability as a function of ambient pressure (Appendix B) for TRMFPAD
experiments. / Thesis (Ph.D, Chemistry) -- Queen's University, 2012-09-11 22:18:20.89
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/7456 |
| Date | 12 September 2012 |
| Creators | Clarkin, OWEN |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
Page generated in 0.0024 seconds