Vacuum ultra-violet photodesorption of CO adsorbed on water ice
松田, 晶平 ,
山﨑, 元気 ,
原田, 明薮下, 彰啓
6 , 2018-02 , 九州大学大学院総合理工学府
Photodesorption of CO is suggested as a possible process which maintains a measurable amount of gaseous CO in cold interstellar clouds. In this study, the 157 nm photodesorption of CO(v = 0) adsorbed on amorphous solid water and polycrystalline ice were investigated at 8–170 K. Photodesorbed CO(v = 0) was detected by (2+1) resonance enhanced multiphoton ionization technique. Time-of-flight spectra of CO(v = 0) reveal the translational energy distributions, from which the possibility of three photodesorption processes are deduced. When the temperature is increased, photodesorption of CO(v = 0) shows four peaks at around 20–30 K, 40–60 K, 65–75 K, and 145–160 K, which are due to CO-bonded OH, CO-dangling OH, structural change from high density to low density amorphous ice, and H2O desorption, respectively.