Control of Tautomerization with Single Copper Atoms

6 Control of Tautomerization with Single Copper Atoms 

This change in the populations can be explained by an electric field and/or a tip proximity effect (i.e., interactions between the tip apex and molecule) and indicates that the tautomerization can be modified through a change of the local surroundings, although the exact origin of the effect remains unclear. 

In order to study the local effect in detail, but with a different origin, single copper atoms have been placed at well-defined adsorption sites close to an individual molecule by STM manipulation [52]. Copper adatoms were created using a soft point contact method [53] in which the STM tip slightly touches a metal surface at the end of a vertical approach. Before this procedure, the W tip is indented 

An important property of the switching process between the two cis tautomers on Cu( 110) is the slight lateral shift of the molecule by 0.02 nm with respect to the copper row underneath (to maximize the interaction between the free N atoms and the copper atoms). Consequently, the molecule slightly moves to the left or to 

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