Probing Copper and Copper-Gold Alloy Surfaces with Space-Quantized Oxygen Molecular Beam

Yasutaka Tsuda; Jessiel Siaron Gueriba; Hirokazu Ueta; Wilson Agerico Diño; Mitsunori Kurahashi; Michio Okada

doi:10.1021/jacsau.2c00156

Probing Copper and Copper-Gold Alloy Surfaces with Space-Quantized Oxygen Molecular Beam

JACS Au. 2022 Jul 21;2(8):1839-1847. doi: 10.1021/jacsau.2c00156. eCollection 2022 Aug 22.

Authors

Yasutaka Tsuda^{1

2}, Jessiel Siaron Gueriba³, Hirokazu Ueta⁴, Wilson Agerico Diño^{3

5}, Mitsunori Kurahashi⁴, Michio Okada^{1

6}

Affiliations

¹ Department of Chemistry, Osaka University, Toyonaka, Osaka 560-0043, Japan.
² Materials Sciences Research Center, Japan Atomic Energy Agency, Sayo-gun, Hyogo 679-5148, Japan.
³ Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan.
⁴ National Institute for Materials Science, Tsukuba, Ibaraki 305-0047, Japan.
⁵ Center for Atomic and Molecular Technologies, Osaka University, Suita, Osaka 565-0871, Japan.
⁶ Institute for Radiation Sciences, Osaka University, Toyonaka, Osaka 560-0043, Japan.

Abstract

The orientation and motion of reactants play important roles in reactions. The small rotational excitations involved render the reactants susceptible to dynamical steering, making direct comparison between experiments and theory rather challenging. Using space-quantized molecular beams, we directly probed the (polar and azimuthal) orientation dependence of O₂ chemisorption on Cu(110) and Cu₃Au(110). We observed polar and azimuthal anisotropies on both surfaces. Chemisorption proceeded rather favorably with the O-O bond axis oriented parallel (vs perpendicular) to the surface and rather favorably with the O-O bond axis oriented along [001] (vs along [1̅10]). The presence of Au hindered the surface from further oxidation, introducing a higher activation barrier to chemisorption and rendering an almost negligible azimuthal anisotropy. The presence of Au also prevented the cartwheel-like rotations of O₂.