In situ scanning tunneling microscopy of1-C₁₈H₃₇SH adlayer

Qing-Min Xu, Li-Jun Wan, Chen Wang, and Chun-Li Bai

Center for Molecular Sciences, Institute of Chemistry,
Chinese Academy of Sciences, Beijing 100080, P. R. China

The adlayer structure of 1-octadecanethiol (1-C₁₈H₃₇SH) is investigated by scanning tunneling microscopy (STM) with chemically (I and S) modified Pt/Ir tips. The molecules form a well-ordered self-assembly monolayer. The S-modified tip was found to be effective to reveal the structural details of thiol groups (SH). Based on the STM results and theoretical calculations, a model for 1-octadecanethiol adlayer is proposed.