Complex structural dynamics at adsorbed alkanethiol layers at Au(111) single-crystal domains

The structure and dynamics of dodecanethiol and butanethiol monolayers adso rbed on Au(lll) at 298 K have been followed by in situ and ex situ scanning tunneling microscopy (STM). Results show that a gaslike initial adsorption stage where monatomic deep pit clustering occurs is followed by an advance d adsorption stage in which adlayer structural changes p(nx1) double right arrow (root 3x root 3)R30 degrees double left right arrow c(4x2) take place . The first change is interpreted as the motion of adsorbed molecules from fee to hcp sites, and the second one is explained by the fluctuations of ad sorbed molecules from hollow to bridge sites. The structural fluctuations a t adsorbate domains occur simultaneously with fluctuations in the size of m onatomic deep pits. These processes reveal the complexity of surface dynami cs of alkanethiol adlayers on Au(lll) at 298 K.