Abstract
Self-assembled monolayers (SAMs) of Au-octanethiolate on Au(111) have been studied using scanning tunneling microscopy (STM). Thermal annealing of the dense (root 3 x root 3)R30 degrees layer at 353 K for 1 h leads to the formation of a (5 root 3 x root 3)R30 degrees striped phase coexisting with the (root 3 x root 3)R30 degrees phase. High-resolution STM imaging shows that the unit cell of the (5 root 3 x root 3)R30 degrees phase consists of four adsorbed Au-thiolate species giving rise to an adsorbate coverage of 0.27 ML. The four Au-thiolate species take the standing-up orientation and occupy inequivalent adsorption sites: one on a bridge site and three on the hollow sites. By drawing connections between the (5 root 3 x root 3)R30 degrees and the (root 3 x root 3)R30 degrees phases, it is found that the adsorption site for Au-thiolate inside the (root 3 x root 3)R30 degrees phase must be either the fec hollow or the hcp hollow site.
Original language | English |
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Pages (from-to) | 9484-9490 |
Number of pages | 7 |
Journal | Langmuir |
Volume | 26 |
Issue number | 12 |
DOIs | |
Publication status | Published - 1 Jun 2010 |