New Center article - Laura Slumstrup, John D. Thrower, Thanja Lamberts, Jessalyn DeVine, Julia C. Santos, Harold Linnartz, Liv Hornekær, Herma M. Cuppen and Sergio Ioppolo
Title: IR-Induced CO Photodesorption from Pure CO Ice and CO on Amorphous Solid Water
Summary:
In dense, interstellar clouds, dust grains are covered in icy mantles where CO is a key component, forming a nonpolar layer on top of H2O ice. The icy grains are constantly exposed to radiation which is dominated by infrared (IR) photons within the dense clouds.
In this collaborative work, several groups worked together on examining the effect of IR irradiation on CO on top of amorphous solid water (ASW) and compared it to the effect on a pure CO ice. We used the FELIX IR Free Electron Laser in Nijmegen, Netherlands, to excite CO and H2O vibrational modes. We found that excitation of vibrational modes in the underlying ASW leads to significant CO desorption, in contrast to direct excitation of the stretching mode of CO which is found to only result in inefficient desorption. Our results indicate that energy transfer within ices on interstellar grains might provide an important route to IR photon-induced desorption of volatile species, such as CO.