Date of Thesis

Summer 2024

Description

Motivated by the necessity of non-LTE models that account for species that are not in Local Thermodynamic Equilibrium (LTE) in Titan’s and Earth’s atmospheres, collisional quenching rates of CO and H2O(g) have been studied. Providing more accurate and precise values of collisional quenching rate coefficients is crucial in the development of more advanced atmospheric models, which are important to fields of science such as meteorology and astronomy. Rates of collisional quenching of CO(v=1,2) by CO and CO(v=2) by N2 at approximately 301-321 K were measured by transient diode laser absorption spectroscopy. The rate coefficients of CO(v=1)-CO, CO(v=2)-CO, and CO(v=2)-N2 are reported as (1.5 ± 0.3) x 10-12 , (2 ± 1) x 10-11, and (0.6 ± 2.1) x 10-12 cm3 molecule-1 s-1 , respectively. An exploratory study of the collisional self-quenching of H2O was also performed, representing the first experimentally measured energy transfer of water vapor, with a tentative rate coefficient of (4 ± 2) x 10-14 cm3 molecule-1 s-1 at approximately 301-321 K. This experiment was difficult to perform due to water’s unique propensity for aggregation, and so it requires further research. Density functional theory (DFT) was employed to predict IR absorption spectra of these aggregate clusters with the goal of better directing future work.

Keywords

energy transfer, gas-phase kinetics, pump-probe spectroscopy, DFT

Access Type

Masters Thesis

Degree Type

Master of Science

Major

Chemistry

First Advisor

Karen J. Castle

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