The Molecular Volcano Revisited: Determination of Crack Propagation and Distribution During the Crystallization of Nanoscale Amorphous Solid Water Films
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- 作者：R. Alan May ; R. Scott Smith ; Bruce D. Kay
- 刊名：The Journal of Physical Chemistry Letters
- 出版年：2012
- 出版时间：February 2, 2012
- 年：2012
- 卷：3
- 期：3
- 页码：327-331
- 全文大小：289K
- 年卷期：v.3,no.3(February 2, 2012)
- ISSN：1948-7185
文摘
Temperature programmed desorption (TPD) is utilized to determine the length distribution of cracks formed through amorphous solid water (ASW) during crystallization. This distribution is determined by monitoring how the thickness of an ASW overlayer alters desorption of an underlayer of O2. As deposited, ASW prevents desorption of O2. During crystallization, cracks form through the ASW and open a path to vacuum, which allows O2 to escape in a rapid episodic release known as the 鈥渕olecular volcano鈥? Sufficiently thick ASW overlayers further trap O2 resulting in a second, higher temperature, O2 desorption peak. The evolution of this trapping peak with overlayer thickness is the basis for determining the length distribution of crystallization-induced cracks spanning the ASW. Reflection absorption infrared spectroscopy (RAIRS) and TPD of multicomponent parfait structures of ASW, O2, and Kr indicate that a preponderance of these cracks propagate down from the outer surface of the ASW.