Adsorbed molecular shuttlecocks: An NIXSW study of Sn phthalocyanine on Ag(111) using Auger electron detection

作者：Woolley R A J^*; Martin C P; Miller G; Dhanak V R; Moriarty P J

来源：Surface Science, 2007, 601(5): 1231-1238.

DOI：10.1016/j.susc.2006.12.030

• X-ray standing wave
• low energy electron diffraction (LEED)
• phthalocyanine
• SnPc
• Ag(111) photoemission
• binding site
• geometry

Normal incidence X-ray standing wave (NIXSW) spectroscopy has been used to determine the orientation of Sri phthalocyanine (SnPc) molecules in a highly ordered, but incommensurate, monolayer on the Ag(111) surface. Our sample preparation procedure differs from that used in previous work on this system [C. Stadler, S. Hansen, F. Pollinger, C. Kumpf, E. Umbach, T.-L. Lee, J. Zegenhagen. Phys. Rev. B 74 (2006) 035404] and leads to a different unit cell with basis vector lengths of similar to 15.0 angstrom and 15.3 angstrom (y = 98 degrees) which is oriented at an angle of similar to 5 degrees to the underlying Ag(111) lattice. Structural parameters extracted from Sri MNN NIXSW spectra indicate that SnPc, a buckled, 'shuttlecock' phthalocyanine, adsorbs in a Sit-down geometry with the Sri atom approximately 2.3 angstrom above the Ag(111) surface plane. Despite the incommensurate nature of the overlayer, we find a surprisingly high coherent fraction for standing wave data taken for the (111) reflection and argue that this arises from the small domain size of the superstructure.

• 出版日期2007-3-1