Investigation of HCFCs through computational and experimental methods

CHED 994

Amanda L. Steber and Rebecca A. Peebles, Department of Chemistry, Eastern Illinois University, 600 Lincoln Ave., Charleston, IL 61920
Ab initio calculations at the MP2/6-311++G(2d,2p) level were used to collect data on the interactions of the hydrochlorofluorocarbons (HCFCs) CHCl2F and CHClF2 with H2O and CO2. These calculations provided energies and dipole moments of several minimum energy structures of each dimer, showing that weak C-HO interactions are prevalent in these complexes; natural bond orbital (NBO) analyses confirm the presence of improper intermolecular hydrogen bonding. Future spectroscopic (infrared and microwave) studies are planned for these species, and a discharge nozzle to produce HCFC radicals is currently being tested. In a complementary project, a Fourier-transform microwave spectrometer was used to study CHCl2F-OCS and CHClF2-OCS complexes. Although the spectra have proven difficult to assign, progress has been made on both dimers. The new information gained on HCFCs through these studies will allow more insight into their behavior in the atmosphere and how they may interact with water, carbon dioxide, and other chemicals.