Speaker
Dr
Samar Moussa
(Columbia University)
Description
The “quasi-liquid layer” (QLL) is a nanoscale region of surface disorder that exists near the melting point of ice (~-30ºC). The presence of this layer is believed to affect gas-ice interactions, uptake coefficients and heterogeneous chemistry in the polar regions. It is also believed that gas-ice interactions can modulate the QLL thickness and induce its formation at temperatures below -30ºC.
Characterization of gas-QLL interactions is a prerequisite for a better understanding of chemistry in the polar regions and gives more accurate insights to polar atmospheric and climate models. We report results for the interaction of HNO3 with zone-refined ice. The QLL layer formation and thickness were determined using ellipsometry. Uptake coefficients were determined using a coated-wall flow tube coupled with chemical ionization mass spectrometry. Experimental data were tested against a thermodynamic model developed in our lab for the QLL on pure ice and on ice with impurities.
Please list some keywords
Zone refined ice, QLL, BL, nitric acid, ellipsometer, thickness
Primary author
Dr
Samar Moussa
(Columbia University)
Co-authors
Ms
Min Kuo
(Columbia University)
Prof.
V.Faye McNeill
(Columbia University)
