Vuv Absorption Spectra Study for Photodesorption of Solid Carbon Monoxide as a Function of Temperature: Wannier-Mott Exciton Formation
Yu-Jung Chen1*, G. M. Muñoz Caro2, M. R. S. McCoustra3, D. Field4
1Physics, National Central University, Taoyuan, Taiwan
2Center of Astrobiology, CSIC-INTA, Madrid, Spain
3Chemical Sciences, Heriot-Watt University, Edinburgh, UK
4Physics, University of Aarhus, Aarhus, Denmark
* Presenter:Yu-Jung Chen,
Ice photodesorption has been considered as a non-thermal process, which contributes the abundance of gas-phase molecules toward the cold interstellar regions. In this work VUV absorption spectra of carbon monoxide ices were measured to evaluate the possible link between the structure and the photodesorption yield of carbon monoxide ice. The temperature dependent VUV spectral shifts (few hundred wavenumbers) were observed that can be reproduced by a simple electrostatic model base on Stark effect on a hole and electron residing several nm wavenumbers apart, identifying the presence of Wannier-Mott excitons.

Keywords: VUV absorption, exciton, photodesorption , carbon monoxide, interstellar ice