C60 Chain Phases on ZnPc/Ag(111) Surfaces: Pattern Formation Driven by Competing Intermolecular Interactions

Published

February 4, 2015

Author(s)

Steven W. Robey, W. Jin, D. B. Dougherty, W. G. Cullen, J. E. Reutt-Robey, J. Weeks, Q. Liu

Abstract

Serpentine chain C60 phases were observed in scanning tunneling microscopy (STM) images of C60 layers on ZnPc or pentacene covered Ag(111) and Au(111) surfaces. This low density, quasi-one-dimensional organization contrasts starkly with the close-packed hexagonal phases observed for C60 layers on the bare metal substrates. STM was used to perform a detailed investigation of chain formation on for C60\ZnPc\Ag(111) heterolayers. Motivated by the similarity of these chain phases and the chain and stripe organization occurring in systems such as dipole fluids, etc., we investigated a model based on competing short-range van der Waals interactions and long-range electrostatic interactions between C60 molecules as an explanation for the driving force behind these monolayer phases. Density functional calculations revealed significant charge transfer to C60 from the Ag(111) substrate, through the intervening ZnPc layer, inducing electrostatic interactions between C60 molecules. Molecular dynamics simulations performed with attractive van der Waals interactions plus repulsive dipole-dipole interactions reproduce the C60 chain phases for dipole moment magnitudes in the range of those suggested by the DFT calculations.

Citation

Journal of Physical Chemistry C

Pub Type

Journals

Citation

Robey, S. , Jin, W. , , D. , , W. , , J. , Weeks, J. and Liu, Q. (2015), C60 Chain Phases on ZnPc/Ag(111) Surfaces: Pattern Formation Driven by Competing Intermolecular Interactions, Journal of Physical Chemistry C (Accessed April 24, 2024)