HYDROGEN AND NITROGEN BROADENED ETHANE AND PROPANE ABSORPTION CROSS SECTIONS

High-resolution infrared absorption cross sections are presented for the $nu_{9}$ band of ethane (C$_{2}$H$_{6}$) at 823 cm$^{-1}$. These cross sections make use of spectra recorded at the Australian Synchrotron using a Fourier transform infrared spectrometer with maximum resolution of 0.00096 cm$^{-1}$. The spectra have been recorded at 150, 120 and 90 K for hydrogen and nitrogen broadened C$_{2}$H$_{6}$. They cover appropriate temperatures, pressures and broadening gases associated with the atmospheres of the Outer Planets and Titan, and will improve atmospheric retrievals. The THz/Far-IR beamline at the Australian Synchrotron is unique in combining a high-resolution Fourier transform spectrometer with an �enclosive flow cooling� (EFC) cell designed to study molecules at low temperatures. The EFC cell is advantageous at temperatures for which the vapor pressure is very low, such as C$_{2}$H$_{6}$ at 90 K. Hydrogen broadened absorption cross sections of propane between 700 and 1200 cm$^{-1}$ will also be presented based on spectra obtained at the Canadian Light Source