Resolved IR spectra of pure CO2 ice (15-75K)

Current laboratory spectra do not fully resolve the CO_2_ ice features. To improve the fitting of the observed CO_2_ features, high-resolution solid-state infrared spectra of pure CO_2_ ice are recorded in the laboratory for a series of astronomically relevant temperatures and at an unprecedented level of detail.

The infrared spectra of pure CO_2_ ice were recorded in the 4000 to 400cm^-1^ (2.5-25um) region at a resolution of 0.1cm^-1^ using Fourier transform infrared spectroscopy. Accurate band positions and band widths (FWHM) of pure CO_2_ ice are presented for temperatures of 15, 30, 45, 60, and 75K. The focus of this spectroscopic work is on the CO_2_ (v2) bending mode, but more accurate data are also reported for the ^12^CO_2_ and ^13^CO_2_ (v3) stretching mode, and CO_2_ (v1+v3) and (2v2+v3) combination bands.