Stability of Partially Fluorinated Phthalocyanine Monolayers: Influence of Hydrogen Bonding Revisited
Abstract
Hydrogen-like bonding between halogen and hydrogen atoms is widely accepted as the driving force in self-ordering process of various molecular layers. A proper understanding of how the molecular periphery influences the self-ordering is crucial for formation of structurally and electronically well-defined interfaces.
To probe the stability of ordered molecular layers of phthalocyanines with various fluorination on the Si(111)-Tl 1 X 1 surface we introduce utilization of a strong electric field of the tip of the scanning tunneling microscope. Ab-initio calculations on extended lattices are used to distinguish molecule-substrate and intermolecular interactions.
A systematic comparison of combinations of phthalocyanines with various fluorination provides an understanding of how the molecular periphery influences the intermolecular interaction. We demonstrate that the straightforward explanation of the process of self-ordering by hydrogen-like bonding is not acceptable in the studied case.