High resolution far infrared spectroscopy of HFC-134a using a collisional cooling cell adapted to a synchrotron source

Abstract

A low temperature (176K), high resolution far-IR spectrum of 1,1,1,2-tetrafluoroethane (HFC-134a) has been recorded at the Australian Synchrotron Far-IR beamline. The ν8 band, located at 665.62cm−1, has been analysed and 4635 ro-vibrational transitions were assigned and confirmed using ground state combination differences. Local perturbations emanating from two interacting dark states were identified, and subsequently treated using two c-axis Coriolis coupling terms. The necessary modifications of a collisional cooling/enclosive flow cooling cell for synchrotron far-IR spectroscopy are outlined.