Structure determination of PF3 adsorption on Cu(100) using X-ray standing waves

SURFACE SCIENCE

卷:602

Article

Kariapper, M. S.²  Fisher, C. J.¹  Woodruff, D. P.¹  Chan, A. S. Y.³  Jones, Robert G.³ 

[1] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands, England

[2] King Fahd Univ Petr & Minerals, Dept Phys, Dhahran 31261, Saudi Arabia

[3] Univ Nottingham, Sch Chem, Dept Phys Chem, Nottingham NG7 2RD, England

关键词: surface structure;    chemisorption;    X-ray standing waves;    copper;    phosphorous trifluoride;   

DOI  :  10.1016/j.susc.2007.11.025

来源: Elsevier

【 摘 要 】

The local structure of the Cu(1 0 0)c(4 x 2)-PF3 adsorption phase has been investigated through the use of normal-incidence X-ray standing waves (NIXSW), monitored by P 1s and F 1s photoemission, together with P K-edge near-edge X-ray absorption fine structure (NEXAFS). NEXAFS shows the molecule to be oriented with its C-3v symmetry axis essentially perpendicular to the surface, while the P NIXSW data show the molecule to be adsorbed in atop sites 2.37 +/- 0.04 angstrom above the surface, this distance corresponding to the Cu-P nearest-neighbour distance in the absence of any surface relaxation. F NIXSW indicates a surprisingly small height difference of the P and F atoms above the surface 0.44 +/- 0.06 angstrom, compared with the value expected for an undistorted gas-phase geometry of 0.77 angstrom, implying significant increases in the F-P-F bond angles. In addition, however, the F NIXSW data indicate that the molecules have a well-defined azimuthal orientation with a molecular mirror plane aligned in a < 0 1 1 > substrate mirror plane, and with a small (5-10 degrees) tilt of the molecule in this plane such that the two symmetrically-equivalent F atoms in each molecule are tilted down towards the surface. (c) 2007 Elsevier B.V. All rights reserved.

【 授权许可】

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