(113f) Computational Investigation of Organic Molecule Assemblies On Cu(111)

The ability to understand and control assembly of molecular-surface interactions, and hence overall assembled molecular adlayers on surfaces, is critical for future design of nanomaterials and nanodevices in areas including electronics and biochemistry.  Copper has shown promise as a relatively low-cost metal which promising surface electronic structure to interact with various molecular species.  Based on intriguing results seen via STM investigations, we will present work from recent density functional theory (DFT) calculations aimed at characterizing the local surface adlayer structure of directed assembled adlayers of several organic molecules on the Cu(111) surface.  Specifically, we will present results related to three distinct assembled adlayers on the Cu(111) surface.  The first system studied is high-coverage adlayers of alanine on Cu(111). Current STM studies show that alanine/Cu(111) can form highly ordered hexagonally tiling local quantum corrals. The calculations performed help lead insight into the possible local atomic structure and hydrogen bonding networks present in the observed quantum corrals of alanine on Cu(111); understanding how to engineer nano-scale confined quantum materials can have applications in practical nanodevice design.   The second system studied is isoleucine on Cu(111).  Isoleucine represents a candidate amino acid with an appreciably large and predicted non-surface-binding side chain for investigation of coverage effects in adlayer assembly on Cu(111).  In particular, this work seeks to determine whether energetic for differing isoleucine adlayer chiral handedness exist, as well as the possibility for higher adlayer density itself between chiral hands of isoleucine. The final system examined involves the directed assembly of buckyball-pentacene chiral pinwheels on Cu(111).  In addition to examining the possibility of using this system for applications in electronic heterojunctions, we perform calculations to determine the local geometry, charge transfer in the chiral pinwheel network as well as the overall thermodynamic driving force for its formation.