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)
