Knowledge Bank

Ultraviolet and infrared spectra are presented for $CO2,CH2O,CD2O,CC\ell 2F2,CH3OH$ and $OsO4$, dissolved in liquified Xe, Kr, and Ar. The infrared absorption features are narrower than the corresponding gas phase vibrational bands but broader than rotational lines. The frequencies of the absorption features are observed to shift with solvent, temperature and Isotopic composition. High densities ($1017$ to $1019$ molecules/$cm3$) are obtainable. Some unstable compounds, such as $CH2O$ monomer at $1018$ molecules/$cm3$, form stable cryogenic solutions. Cryogenic solutions are shown to be useful for spectroscopic detection of parts per million to parts per billion impurities in gases and for photochemically induced isotope separation.""