Stabilization dynamics of the ozone molecular system

<p>"The observation of larger-than-expected concentrations of heavier isotopologues of ozone known as 'ozone isotopic anomaly' in the stratosphere is a mass-independent effect (in contrast to most kinetic isotope effects familiar to chemists) that is traced back to the recombination process in the formation of ozone in the Chapman cycle. Understanding the relative efficiencies (often approximated as equal for different isotopologues) of the stabilization step (some of the details of which are still a mystery) which involves energy transfer from a highly excited ozone molecule to a third body, M (argon atom in this case) to form stable ozone is a possible path to insight into the phenomenon.</p><p>This research discusses theoretical studies of the energy transfer mechanism of the stabilization step. A potential energy surface (PES) is constructed with an electronic structure method that best describes the electronic energy of the O₃-Ar complex as a function of its geometry, with which the dynamics of this process is studied. Isotopic substitution of O₃ is necessary to study the anomaly. The PESs for the isotopologues: ¹⁶O¹⁸O¹⁶O-Ar and ¹⁶O¹⁶O¹⁸O-Ar are also constructed by straightforward transformation of the coordinate system (no new electronic structure data was needed). The spectroscopy and scattering of ¹⁶O¹⁶O¹⁶O-Ar and its isotopologues are studied using the developed PES for the complex to gain insight into the process.</p><p>There is roughly a doubling of the density of allowed quantum states observed for the asymmetric ¹⁶O¹⁶O¹⁸O-Ar isotopologue compared to ¹⁶O¹⁶O¹⁶O-Ar and ¹⁶O¹⁸O¹⁶O-Ar owing to slight change in masses reflecting in the rotational constants, quantum nuclear spin statistics of bosons and symmetry rules. The total rate for ¹⁶O¹⁶O¹⁸O-Ar is also higher than ¹⁶O¹⁶O¹⁶O-Ar due to small changes in the reduced mass of the collision system. With ozone being formed and destroyed continuously in the stratosphere, a small bias could lead to the accumulation of a favored isotopologue"--Abstract, page iv.</p>

Name thesis:degree_name

Ph. D. in Chemistry

Grantor

Missouri University of Science and Technology

Author dc:creator

• Sur, Sangeeta

• Inelastic scattering
• O3-Ar
• Quantum dynamics
• MCTDH
• Potential energy surface
• L-IMLS method
• Rovibrational bound states
• Chemistry

Repository record dc:identifier

https://scholarsmine.mst.edu/doctoral_dissertations/2875

OAI identifier oai:identifier

oai:scholarsmine.mst.edu:doctoral_dissertations-3880