Temperature effect on IR structural changes of CO₂ ice

Ni-En Sie^1*, G. M. Muñoz Caro², Chao-Hui Huang¹, Yu-Jung Chen¹

¹Department of Physics, National Central University, Taoyuan City, Taiwan
²Centro de Astrobiología, INTA-CSIC, Madrid, Spain

* Presenter:Ni-En Sie, email:niensie@phy.ncu.edu.tw

According to literature, CO₂ ice has a phase transition from amorphous to crystalline structure at ~50 K, which has an obvious variation on IR spectra, showing a high sensitivity on environmental temperature. In this study, the 10 ML CO₂ ice is deposited at 12−70 K, as well as warmed up to 100 K for the complete thermal desorption. In two sets of experiments, the IR profiles show a huge difference during temperature-programed desorption (TPD) process versus deposition temperature. This is the first comprehensive work investigating the detail structural features of amorphous and crystalline bands in CO₂ ice, furthermore, comparing the profiles of temperature-processed ice. Through these detailed experiments and analysis, the spectra collected in various conditions can be utilized with the observation data.

Keywords: Carbon dioxide, Structure, FTIR, TPD