Molecularly resolved observation of anisotropic intermolecular force in a formate-ion monolayer on a TiO2(110) surface by scanning tunneling microscopy

被引：37

作者：

Onishi, H ^{[1
]}

Fukui, K ^{[1
]}

Iwasawa, Y ^{[1
]}

机构：

[1] UNIV TOKYO,GRAD SCH SCI,DEPT CHEM,BUNKYO KU,TOKYO 113,JAPAN

来源：

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS | 1996年 / 109卷

关键词：

carboxylic acid; intermolecular force; nanostructure; scanning tunneling microscopy; surface diffusion; titanium oxide;

D O I：

10.1016/0927-7757(95)03465-X

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The diffusion kinetics of adsorbed formate ions have been observed on a TiO2 (110) surface by scanning tunneling microscopy (STM) operated under ultrahigh vacuum. Formate ions in a desired area are removed without damage to the substrate, by rastering the monolayer with a high-biased STM tip. A patch of uncovered substrate is thus created in a (2 x 1)-formate monolayer. Time-resolved STM observation reveals the transport kinetics of individual formate ions filling the void. The anisotropic rate of migration suggests that a row of Ti ions exposed on the substrate presents a one-dimensional channel for formate transport. A significant anisotropy in formate-formate interaction is further postulated from the kinetics; a repulsive force between formate ions neighboring on a Ti row drives them to migrate, whereas an attractive force between formates on adjacent Ti-rows plays a secondary role in regulating overlayer structure. The present study shows how STM images document the anisotropy in intermolecular force regulating an adsorbate overlayer on a solid surface, by taking advantage of the relaxation of a nanometer-sized structure fabricated in the overlayer.

引用

页码：335 / 343

页数：9