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The adsorbed structures of 4_pentyl4′-methoxy_phenylbenzoate on highly oriented pyrolytic graphite (HOPG) are studied by scanning tunneling microscope (STM) at room temperature with near atomic level resolution. It is observed that the STM images could reveal the regular two_dimensional arrangement of molecules. The computer calculation is performed to determine the contrast mechanism of the STM images associated with the tip_to_sample electric field. The results indicate that the STM images of the liquid crystal may be jointly affected by the modulation of the local work function of the substrate covered with the polarizable molecular adsorbates and the variation of density of states of the adsorbed molecules.
The adsorbed structures of 4_pentyl4’-methoxy_phenylbenzoate on highly oriented pyrolytic graphite (HOPG) were studied by scanning tunneling microscope (STM) at room temperature with near atomic level resolution. It is observed that the STM images could reveal the regular two_dimensional arrangement of molecules. The results of the STM calculations of the contrast mechanism of the STM images associated with the tip_to_sample electric field. The results indicate that the STM images of the liquid crystal may be jointly affected by the modulation of the local work function of the substrate covered with the polarizable molecular adsorbates and the variation of density of states of the adsorbed molecules.