Weak interactions and CO2 microsolvation in the cis-1,2-difluoroethylene...CO2 complex

Peebles, Rebecca A.

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https://hdl.handle.net/2142/97066 Copy

Description

Title

Weak interactions and CO2 microsolvation in the cis-1,2-difluoroethylene...CO2 complex

Author(s)

Peebles, Rebecca A.

Contributor(s)

• Peebles, Sean A.
• Trendell, William

Issue Date

2017-06-22

Keyword(s)

Clusters/complexes

Abstract

The need for a deep understanding of chem{CO_2} interactions is significant given the importance of supercritical chem{CO_2} (sc-chem{CO_2}) as a green solvent. Fluorinated compounds often have higher solubility in sc-chem{CO_2} than their hydrocarbon analogs, and the reasons for this are not well understood. Investigations of dimers of one chem{CO_2} molecule with a simple fluorinated hydrocarbon provide an initial step towards understanding the complex balance of forces that is likely to be present as a larger solvation shell of sc-chem{CO_2} is built._x000d_ _x000d_ The weakly bound dimer {it cis}-1,2-difluoroethylene...chem{CO_2} is the latest in a series of complexes of chem{CO_2} with fluorinated ethylenes that has recently been studied using chirped-pulse (CP) Fourier-transform microwave spectroscopy. Unlike all previous members of the series, the observed structure of {it cis}-1,2-difluoroethylene...chem{CO_2} is nonplanar, with chem{CO_2} sitting above the ethylene plane and crossed relative to the C=C bond. This nonplanar arrangement is consistent with predictions made using symmetry adapted perturbation theory (SAPT), where the dispersion energy of the nonplanar structure is significantly more favorable than for a structure where chem{CO_2} lies in the same plane as the ethylene moiety. Observed transitions are doubled as a result of chem{CO_2} tunneling between equivalent positions above and below the ethylene plane, leading to inversion of the $mu_c$ dipole moment component. Observed transitions for the most abundant isotopologue have been fitted to a two state Hamiltonian to give an energy difference between tunneling states of $Delta E approx 333$ MHz, and analysis using Meyer's one dimensional model to determine the barrier to inversion is presently in progress.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/97066

DOI

https://doi.org/10.15278/isms.2017.RH04

Copyright and License Information

Copyright 2017 Rebecca A. Peebles

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