Chemistry Chemistry Seminar - Student Thesis Talk; Megan Tracy.

Megan Tracy. Seminar Title: "Determining the Structure of 2-chloro-3,3,3-Trifluoropropene and its Dimers with Argon and Hydrogen Fluoride."
Abstract: When molecules change rotational energy levels, they release or absorb energy of a specific, set amount, typically as light in the microwave region of the electromagnetic spectrum of a specific, set frequency, which is able to be predicted based on the rotational constants of the molecule, which correlate to the molecule’s structure based on its moments of inertia. The structure of 2-chloro-3,3,3-trifluoropropene was thus determined based on the assignment of the Fourier-transform microwave spectrum of the gas to the ab initio calculated rotational transition peaks based on the minimum energy structure predicted by Gaussian09. The corresponding spectra of each of the three C-13 singly-substituted isotopologues of the molecule, the Cl-37 singly substituted isotopologue, and the three doubly substituted C-13 and Cl-37 isotopologues were also assigned, with the addition of Balle-Flygare narrow band spectroscopy to measure transitions that are too weak to be obtained in the broadband spectrum, and the rotational constants calculated based on these assignments were used in Kraitchman calculations to further define the position of the different atoms within the molecule. Using this structure of the molecule, the structure and rotational constants of the minimum energy arrangement of the molecule’s dimer with argon were predicted by Gaussian09 and were used to generate a predicted spectrum, which is currently being assigned to the chirped pulse broad band spectrum of the gas. This thesis will involve studying the dimer of the molecule with HF in this manner, and future work will likely involve the other protic acids HCl and HCCH.