Sigurbjörnsson Omar F, Signorell Ruth
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada.
Phys Chem Chem Phys. 2008 Nov 7;10(41):6211-4. doi: 10.1039/b811709h. Epub 2008 Sep 11.
Recent evidence for ethane clouds and condensation in Titan's atmosphere raise the question whether liquid ethane condensation nuclei and supercooled liquid ethane droplets exist under the prevalent conditions. We present laboratory studies on the phase behaviour of pure ethane aerosols and ethane aerosols formed in the presence of other ice nuclei under conditions relevant to Titan's atmosphere. Combining bath gas cooling with infrared spectroscopy, we find evidence for the existence of supercooled liquid ethane aerosol droplets. The observed homogeneous freezing rates imply that supercooled ethane could be a long-lived species in ethane-rich regions of Titan's atmosphere similar to supercooled water in the Earth's atmosphere.
近期关于土卫六大气中乙烷云及凝结现象的证据，引发了一个问题：在普遍存在的条件下，液态乙烷凝结核和过冷液态乙烷液滴是否存在。我们展示了在与土卫六大气相关的条件下，对纯乙烷气溶胶以及在其他冰核存在时形成的乙烷气溶胶的相行为进行的实验室研究。通过将浴气冷却与红外光谱相结合，我们发现了过冷液态乙烷气溶胶液滴存在的证据。观测到的均匀冻结速率表明，过冷乙烷在土卫六大气中富含乙烷的区域可能是一种长寿物质，类似于地球大气中的过冷水。
