FT-IR SPECTROSCOPY OF THE CFC REPLACEMENTS HFC-152A AND HFC-227EA IN A SUPERSONIC JET EXPANSION

Infrared spectra of the CFC and Halon replacements HFC-152a (1,1-diflu oroethane) and HFC-227ea (1,1,1,2,3,3,3-heptafluoropropane) have been recorded in a supersonic jet expansion. The resultant rotationally col d spectra have been used in combination with ab initio calculations to reassign the spectra of HFC-152a and begin an assignment of HFC-227ea . High-resolution spectra have been recorded and for HFC-152a two fund amentals assigned. A least-squares fit of combination differences from these bands, together with the available microwave transitions, has l ed to an improved set of ground state rotational constants.