THz time-domain spectroscopy of interstellar ice analogs

Abstract

International astronomical facilities, in particular the Herschel Space Telescope, SOFIA and ALMA, are currently characterizing the interstellar medium (ISM) by collecting a huge amt. of new THz spectral data that must be compared to THz lab. spectra to be interpreted. The latter, however, are largely lacking, and this severely restricts the scientific impact of the astronomical observations. We have recently constructed a new THz time-domain spectroscopy system to investigate the spectra of interstellar relevant ice analogs in the range between 0.3 - 7 THz. The system is coupled to a FT-IR spectrometer to monitor the ices in the mid-IR (4000 - 500 cm^(-1)). This talk will focus on the lab. investigation of the compn. and structure of the bulk phases of interstellar ice analogs (i.e., H_2O, CO_2, CO, CH_3OH, NH_3, CH_4). The ultimate goal of this research project is to provide the scientific community with an extensive THz ice-database, which will allow quant. studies of the ISM, and guide future astronomical observations of species in the solid phase.