Jan 7 – 12, 2018
ETH Zürich, centre
Europe/Zurich timezone

Interaction of Low Energy (0-20 eV) Electrons with Sulfur Dioxide on Ice Surfaces

Jan 9, 2018, 12:35 PM
1h 30m
NO Building, Room C 60 (ETH Zürich, centre)

NO Building, Room C 60

ETH Zürich, centre

Sonneggstrasse 5 8092 Zürich

Speaker

Mr Jaehyeock Bang (Department of Chemistry, Seoul National University)

Description

We studied the interaction of low energy (0-20 eV) electrons with sulfur dioxide (SO₂) on a crystalline ice film surface. An ice film was prepared by H2O vapor deposition on a Pt(111) substrate at 150 K for thickness of >100 BL inside a vacuum chamber and was annealed at 165 K to produce a crystalline ice film with a flat (0001) surface. SO₂ gas was adsorbed on the crystalline ice film through a tube doser. The surface adsorbates were analyzed using the methods of Cs+ reactive ion scattering (RIS) and low energy sputtering (LES), which revealed molecular SO2 adsorption at ~95 K and the occurrence of the hydrolysis of SO₂ at >100 K.¹ We irradiated low energy electrons, produced from an electron flood gun, onto the ice film surface with adsorbed SO₂ at 95 K. While the low energy electrons transmit through an ice film, they were trapped quite efficiently by the SO₂ adsorbates on the surface. The amount of SO2–trapped electrons was estimated by measuring the film voltage with a Kelvin probe at various incident energies of the electrons. RIS and LES measurements of the surface show that the electron-trapping by SO2 produces various negative ion species, such as OH⁻, SO₂⁻, SO₃⁻, and HSO₃⁻. (1) Bang, J.; Shoaib, M. A.; Choi, C. H.; Kang, H. Efficient Thermal Reactions of Sulfur Dioxide on Ice Surfaces at Low Temperature: A Combined Experimental and Theoretical Study. ACS Earth and Space Chem. 2017

Significance statement

SO₂ adsorbates on crystalline ice film can trap low energy (0-20 eV) electrons, and it produces various negative ion species such as OH⁻, SO₂⁻, SO₃⁻, and HSO₃⁻ at 95 K.

Primary author

Mr Jaehyeock Bang (Department of Chemistry, Seoul National University)

Co-author

Prof. Heon Kang (Department of Chemistry, Seoul National University)

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