Fast Scanning Calorimetry studies of dynamics and phase transitions in condensed molecular phases by Rinipal Kaur, GW Graduate Student, Sadtchenko Lab

 The Department of Chemistry Presents, via Webinar:  Rinipal Kaur, Graduate Student, GW Department of Chemistry, Sadtchenko Lab

Ice plays a critical role in a multitude of natural environments. For instance, polycrystalline ice may act as a dynamic substrate for a range of chemical processes, which may release greenhouse gases and other pollutants as a result of biochemical reaction in thawing permafrost. Crystalline ice nuclei are also important because they often acts as precursors for cloud and fog formation. Earlier studies yielded a plethora of information on vaporization rates and mass accommodation coefficients (MAC) values of water molecules on the ice surfaces. Yet the inferred values vary by three orders of magnitude. To resolve this long standing controversy, I have explored the vaporization rates of ice at temperatures near its melting point using advanced fast scanning calorimetry (FSC) technique. According to my measurements, the kinetics of water uptake and desorption are inconsistent with the conventional mobile precursor (MP) model.  In fact, The MAC values that I have measured are near unity. This introduces terra nova in the way we analyze vaporization rates and MAC values in the environmentally relevant temperature range from -50 to 0 oC. I will also describe the pioneering results of my FSC experiments that were designed to explore phase transformations of aqueous phase at grain boundaries in polycrystalline ice. 

Bio   Rinipal Kaur received her M.S in chemistry from Thapar University in Patiala, India.  Ms. Kaur’s current research under Prof. Sadtchenko focuses on studies of phase transformation processes using a novel technique called Fast Scanning Calorimetry to study the organic model glassy films of methyl benzene and crystalline ice films which have relevance to atmospheric chemistry.  

https://gwu.webex.com/gwu/j.php?MTID=ma64b8f83e585fc89ead2554725544623

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