Investigation of the Scanning Tunneling Microscopy Image,the Stacking Pattern,and the Bias-Voltage-Dependent Structural Instability of l,10'-Phenanthroline Molecules Adsorbed on Au(111)in Terms of Electronic Structure Calculations

摘要

A self-assembled monolayer of l,10'-phenanthroline(phen)molecules on Au(111)was found to undergo a structural phase transition when the bias voltage is switched in scanning tunneling microscopy(STM)experiments(Phys.Rev.Lett.1995,75,2376;Surf.Sci.1997,389,19).The nature of two bright spots representing each phen molecule in the high-resolution STM images of phen molecules on Au(111)was identified by calculating the partial density plots for a monolayer of phen molecules adsorbed on Au(111)with tight-binding electronic structure calculations.The stacking pattern of chains of phen molecules on Au(111)was explained by studying the intermolecular interactions between phen molecules on the basis of first-principles electronic structure calculations for a phen dimer,(phen)_2.The structural instability of phen molecule arrangement caused by the bias-voltage switch was probed by estimating the adsorbate-surface interaction energy with the point-charge approximation for Au(111).